Enhancement of the channel propagation matrix order and rank for a wireless channel

ABSTRACT

Enhancement of wireless Channel Order and rank (ECHO) systems and ECHO repeater devices for enhancement of a wireless propagation channel for point to point or point to multipoint radio configurations are disclosed. The enhancement may be used for MIMO communications channels. Aspects support a richer multipath environment to increase the rank of the channel propagation matrix and/or to increase the magnitude of the coefficients of the propagation matrix between two or more radios. Such enhancement is applicable to backhaul radios in terms of increased range or in the number of supportable information streams. The installation, provisioning, optimization, control, monitoring, and adaptation of such devices within a network of backhaul radios is also disclosed. Wireless links and control between IBR and ECHO devices, and between ECHO devices and other ECHO devices, are also disclosed.

PRIORITY

The present application is a continuation application of U.S. patentapplication Ser. No. 13/763,530, filed on Feb. 8, 2013, entitled“ENHANCEMENT OF THE CHANNEL PROPAGATION MATRIX ORDER AND RANK FOR AWIRELESS CHANNEL”, the entirety of which is hereby incorporated byreference.

BACKGROUND

1. Field

The present disclosure relates generally to data networking and inparticular to a backhaul radio for connecting remote edge accessnetworks to core networks.

2. Related Art

Data networking traffic has grown at approximately 100% per year forover 20 years and continues to grow at this pace. Only transport overoptical fiber has shown the ability to keep pace with thisever-increasing data networking demand for core data networks. Whiledeployment of optical fiber to an edge of the core data network would beadvantageous from a network performance perspective, it is oftenimpractical to connect all high bandwidth data networking points withoptical fiber at all times. Instead, connections to remote edge accessnetworks from core networks are often achieved with wireless radio,wireless infrared, and/or copper wireline technologies.

Radio, especially in the form of cellular or wireless local area network(WLAN) technologies, is particularly advantageous for supportingmobility of data networking devices. However, cellular base stations orWLAN access points inevitably become very high data bandwidth demandpoints that require continuous connectivity to an optical fiber corenetwork.

When data aggregation points, such as cellular base station sites, WLANaccess points, or other local area network (LAN) gateways, cannot bedirectly connected to a core optical fiber network, then an alternativeconnection, using, for example, wireless radio or copper wirelinetechnologies, must be used. Such connections are commonly referred to as“backhaul.”

Many cellular base stations deployed to date have used copper wirelinebackhaul technologies such as T1, E1, DSL, etc. when optical fiber isnot available at a given site. However, the recent generations of HSPA+and LTE cellular base stations have backhaul requirements of 100 Mb/s ormore, especially when multiple sectors and/or multiple mobile networkoperators per cell site are considered. WLAN access points commonly havesimilar data backhaul requirements. These backhaul requirements cannotbe practically satisfied at ranges of 300 m or more by existing copperwireline technologies. Even if LAN technologies such as Ethernet overmultiple dedicated twisted pair wiring or hybrid fiber/coax technologiessuch as cable modems are considered, it is impractical to backhaul atsuch data rates at these ranges (or at least without adding intermediaterepeater equipment). Moreover, to the extent that such special wiring(i.e., CAT 5/6 or coax) is not presently available at a remote edgeaccess network location; a new high capacity optical fiber isadvantageously installed instead of a new copper connection.

Rather than incur the large initial expense and time delay associatedwith bringing optical fiber to every new location, it has been common tobackhaul cell sites, WLAN hotspots, or LAN gateways from offices,campuses, etc. using microwave radios. An exemplary backhaul connectionusing the microwave radios 132 is shown in FIG. 1. Traditionally, suchmicrowave radios 132 for backhaul have been mounted on high towers 112(or high rooftops of multi-story buildings) as shown in FIG. 1, suchthat each microwave radio 132 has an unobstructed line of sight (LOS)136 to the other. These microwave radios 132 can have data rates of 100Mb/s or higher at unobstructed LOS ranges of 300 m or longer withlatencies of 5 ms or less (to minimize overall network latency).

Traditional microwave backhaul radios 132 operate in a Point-to-point(PTP) configuration using a single “high gain” (typically >30 dBi oreven >40 dBi) antenna at each end of the link 136, such as, for example,antennas constructed using a parabolic dish. Such high gain antennasmitigate the effects of unwanted multipath self-interference or unwantedco-channel interference from other radio systems such that high datarates, long range and low latency can be achieved. These high gainantennas however have narrow radiation patterns.

Furthermore, high gain antennas in traditional microwave backhaul radios132 require very precise, and usually manual, physical alignment oftheir narrow radiation patterns in order to achieve such highperformance results. Such alignment is almost impossible to maintainover extended periods of time unless the two radios have a clearunobstructed line of sight (LOS) between them over the entire range ofseparation. Furthermore, such precise alignment makes it impractical forany one such microwave backhaul radio to communicate effectively withmultiple other radios simultaneously (i.e., a “point-to-multipoint”(PMP) configuration).

In wireless edge access applications, such as cellular or WLAN, advancedprotocols, modulation, encoding and spatial processing across multipleradio antennas have enabled increased data rates and ranges for numeroussimultaneous users compared to analogous systems deployed 5 or 10 yearsago for obstructed LOS propagation environments where multipath andco-channel interference were present. In such systems, “low gain”(usually <6 dBi) antennas are generally used at one or both ends of theradio link both to advantageously exploit multipath signals in theobstructed LOS environment and allow operation in different physicalorientations as would be encountered with mobile devices. Althoughimpressive performance results have been achieved for edge access, suchresults are generally inadequate for emerging backhaul requirements ofdata rates of 100 Mb/s or higher, ranges of 300 m or longer inobstructed LOS conditions, and latencies of 5 ms or less.

In particular, “street level” deployment of cellular base stations, WLANaccess points or LAN gateways (e.g., deployment at street lamps, trafficlights, sides or rooftops of single or low-multiple story buildings)suffers from problems because there are significant obstructions for LOSin urban environments (e.g., tall buildings, or any environments wheretall trees or uneven topography are present).

FIG. 1 illustrates edge access using conventional unobstructed LOS PTPmicrowave radios 132. The scenario depicted in FIG. 1 is common for many2^(nd) Generation (2G) and 3^(rd) Generation (3G) cellular networkdeployments using “macrocells”. In FIG. 1, a Cellular Base TransceiverStation (BTS) 104 is shown housed within a small building 108 adjacentto a large tower 112. The cellular antennas 116 that communicate withvarious cellular subscriber devices 120 are mounted on the towers 112.The PTP microwave radios 132 are mounted on the towers 112 and areconnected to the BTSs 104 via an nT1 interface. As shown in FIG. 1 byline 136, the radios 132 require unobstructed LOS.

The BTS on the right 104 a has either an nT1 copper interface or anoptical fiber interface 124 to connect the BTS 104 a to the Base StationController (BSC) 128. The BSC 128 either is part of or communicates withthe core network of the cellular network operator. The BTS on the left104 b is identical to the BTS on the right 104 a in FIG. 1 except thatthe BTS on the left 104 b has no local wireline nT1 (or optical fiberequivalent) so the nT1 interface is instead connected to a conventionalPTP microwave radio 132 with unobstructed LOS to the tower on the right112 a. The nT1 interfaces for both BTSs 104 a, 104 b can then bebackhauled to the BSC 128 as shown in FIG. 1.

FIG. 2A is a block diagram of the major subsystems of a conventional PTPmicrowave radio 200A for the case of Time-Division Duplex (TDD)operation, and FIG. 2B is a block diagram of the major subsystems of aconventional PTP microwave radio 200B for the case of Frequency-DivisionDuplex (FDD) operation.

As shown in FIG. 2A and FIG. 2B, the conventional PTP microwave radiotraditionally uses one or more (i.e. up to “n”) T1 interfaces 204A and204B (or in Europe, E1 interfaces). These interfaces (204A and 204B) arecommon in remote access systems such as 2G cellular base stations orenterprise voice and/or data switches or edge routers. The T1 interfacesare typically multiplexed and buffered in a bridge (e.g., the InterfaceBridge 208A, 208B) that interfaces with a Media Access Controller (MAC)212A, 212B.

The MAC 212A, 212B is generally denoted as such in reference to asub-layer of Layer 2 within the Open Systems Interconnect (OSI)reference model. Major functions performed by the MAC include theframing, scheduling, prioritizing (or “classifying”), encrypting anderror checking of data sent from one such radio at FIG. 2A or FIG. 2B toanother such radio. The data sent from one radio to another is generallyin a “user plane” if it originates at the T1 interface(s) or in the“control plane” if it originates internally such as from the Radio LinkController (RLC) 248A, 248B shown in FIG. 2A or FIG. 2B.

With reference to FIGS. 2A and 2B, the Modem 216A, 216B typicallyresides within the “baseband” portion of the Physical (PHY) layer 1 ofthe OSI reference model. In conventional PTP radios, the baseband PHY,depicted by Modem 216A, 216B, typically implements scrambling, forwarderror correction encoding, and modulation mapping for a single RFcarrier in the transmit path. In receive, the modem typically performsthe inverse operations of demodulation mapping, decoding anddescrambling. The modulation mapping is conventionally QuadratureAmplitude Modulation (QAM) implemented with In-phase (I) andQuadrature-phase (Q) branches.

The Radio Frequency (RF) 220A, 220B also resides within the PHY layer ofthe radio. In conventional PTP radios, the RF 220A, 220B typicallyincludes a single transmit chain (Tx) 224A, 224B that includes I and Qdigital to analog converters (DACs), a vector modulator, optionalupconverters, a programmable gain amplifier, one or more channelfilters, and one or more combinations of a local oscillator (LO) and afrequency synthesizer. Similarly, the RF 220A, 220B also typicallyincludes a single receive chain (Rx) 228A, 228B that includes I and Qanalog to digital converters (ADCs), one or more combinations of an LOand a frequency synthesizer, one or more channel filters, optionaldownconverters, a vector demodulator and an automatic gain control (AGC)amplifier. Note that in many cases some of the one or more LO andfrequency synthesizer combinations can be shared between the Tx and Rxchains.

As shown in FIGS. 2A and 2B, conventional PTP radios 200A, 200B alsoinclude a single power amplifier (PA) 232A, 232B. The PA 232A, 232Bboosts the transmit signal to a level appropriate for radiation from theantenna in keeping with relevant regulatory restrictions andinstantaneous link conditions. Similarly, such conventional PTP radios232A, 232B typically also include a single low-noise amplifier (LNA)236, 336 as shown in FIGS. 2A and 2B. The LNA 236A, 236B boosts thereceived signal at the antenna while minimizing the effects of noisegenerated within the entire signal path.

As described above, FIG. 2A illustrates a conventional PTP radio 200Afor the case of TDD operation. As shown in FIG. 2A, conventional PTPradios 200A typically connect the antenna 240A to the PA 232A and LNA236A via a band-select filter 244A and a single-pole, single-throw(SPST) switch 242A.

As described above, FIG. 2B illustrates a conventional PTP radio 200Bfor the case of FDD operation. As shown in FIG. 2B, in conventional PTPradios 200B, then antenna 240B is typically connected to the PA 232B andLNA 236B via a duplexer filter 244B. The duplexer filter 244B isessentially two band-select filters (tuned respectively to the Tx and Rxbands) connected at a common point.

In the conventional PTP radios shown in FIGS. 2A and 2B, the antenna240A, 240B is typically of very high gain such as can be achieved by aparabolic dish so that gains of typically >30 dBi (or even sometimes >40dBi), can be realized. Such an antenna usually has a narrow radiationpattern in both the elevation and azimuth directions. The use of such ahighly directive antenna in a conventional PTP radio link withunobstructed LOS propagation conditions ensures that the modem 216A,216B has insignificant impairments at the receiver (antenna 240A, 240B)due to multipath self-interference and further substantially reduces thelikelihood of unwanted co-channel interference due to other nearby radiolinks.

Although not explicitly shown in FIGS. 2A and 2B, the conventional PTPradio may use a single antenna structure with dual antenna feedsarranged such that the two electromagnetic radiation patterns emanatedby such an antenna are nominally orthogonal to each other. An example ofthis arrangement is a parabolic dish. Such an arrangement is usuallycalled dual-polarized and can be achieved either by orthogonal verticaland horizontal polarizations or orthogonal left-hand circular andright-hand circular polarizations.

When duplicate modem blocks, RF blocks, and PA/LNA/switch blocks areprovided in a conventional PTP radio, then connecting each PHY chain toa respective polarization feed of the antenna allows theoretically up totwice the total amount of information to be communicated within a givenchannel bandwidth to the extent that cross-polarizationself-interference can be minimized or cancelled sufficiently. Such asystem is said to employ “dual-polarization” signaling. Such systems maybe referred to as having two “streams” of information, whereas multipleinput multiple output (MIMO) systems utilizing spatial multiplexing mayachieve successful communications using even more than two streams, inpractice.

When an additional circuit (not shown) is added to FIG. 2A that canprovide either the RF Tx signal or its anti-phase equivalent to eitherone or both of the two polarization feeds of such an antenna, then“cross-polarization” signaling can be used to effectively expand theconstellation of the modem within any given symbol rate or channelbandwidth. With two polarizations and the choice of RF signal or itsanti-phase, then an additional two information bits per symbol can becommunicated across the link. Theoretically, this can be extended andexpanded to additional phases, representing additional information bits.At the receiver, for example, a circuit (not shown) could detect if thetwo received polarizations are anti-phase with respect to each other, ornot, and then combine appropriately such that the demodulator in themodem block can determine the absolute phase and hence deduce the valuesof the two additional information bits. Cross-polarization signaling hasthe advantage over dual-polarization signaling in that it is generallyless sensitive to cross-polarization self-interference but for highorder constellations such as 64-QAM or 256-QAM, the relative increase inchannel efficiency is smaller.

In the conventional PTP radios shown in FIGS. 2A and 2B, substantiallyall the components are in use at all times when the radio link isoperative. However, many of these components have programmableparameters that can be controlled dynamically during link operation tooptimize throughput and reliability for a given set of potentiallychanging operating conditions. The conventional PTP radios of FIGS. 2Aand 2B control these link parameters via a Radio Link Controller (RLC)248A, 248B. The RLC functionality is also often described as a LinkAdaptation Layer that is typically implemented as a software routineexecuted on a microcontroller within the radio that can access the MAC212A, 212B, Modem 216A, 216B, RF 220A, 220B and/or possibly othercomponents with controllable parameters. The RLC 248A, 248B typicallycan both vary parameters locally within its radio and communicate with apeer RLC at the other end of the conventional PTP radio link via“control frames” sent by the MAC 212A, 212B with an appropriateidentifying field within a MAC Header.

Typical parameters controllable by the RLC 248A, 248B for the Modem216A, 216B of a conventional PTP radio include encoder type, encodingrate, constellation selection and reference symbol scheduling andproportion of any given PHY Protocol Data Unit (PPDU). Typicalparameters controllable by the RLC 248A, 248B for the RF 220A, 220B of aconventional PTP radio include channel frequency, channel bandwidth, andoutput power level. To the extent that a conventional PTP radio employstwo polarization feeds within its single antenna, additional parametersmay also be controlled by the RLC 248A, 248B as self-evident from thedescription above.

In conventional PTP radios, the RLC 248A, 248B decides, usuallyautonomously, to attempt such parameter changes for the link in responseto changing propagation environment characteristics such as, forexample, humidity, rain, snow, or co-channel interference. There areseveral well-known methods for determining that changes in thepropagation environment have occurred such as monitoring the receivesignal strength indicator (RSSI), the number of or relative rate of FCSfailures at the MAC 212A, 212B, and/or the relative value of certaindecoder accuracy metrics. When the RLC 248A, 248B determines thatparameter changes should be attempted, it is necessary in most casesthat any changes at the transmitter end of the link become known to thereceiver end of the link in advance of any such changes. Forconventional PTP radios, and similarly for many other radios, there areat least two well-known techniques which in practice may not be mutuallyexclusive. First, the RLC 248A, 248B may direct the PHY, usually in theModem 216A, 216B relative to FIGS. 2A and 2B, to pre-pend a PHY layerconvergence protocol (PLCP) header to a given PPDU that includes one ormore (or a fragment thereof) given MPDUs wherein such PLCP header hasinformation fields that notify the receiving end of the link ofparameters used at the transmitting end of the link. Second, the RLC248A, 248B may direct the MAC 212A, 212B to send a control frame,usually to a peer RLC 248A, 248B, including various information fieldsthat denote the link adaptation parameters either to be deployed or tobe requested or considered.

The foregoing describes at an overview level the typical structural andoperational features of conventional PTP radios which have been deployedin real-world conditions for many radio links where unobstructed (orsubstantially unobstructed) LOS propagation was possible. Theconventional PTP radio on a whole is completely unsuitable forobstructed LOS PTP or PMP operation.

More recently, as briefly mentioned, there has been significant adoptionof so-called multiple input multiple output (MIMO) techniques, whichutilize spatial multiplexing of multiple information streams between aplurality of transmission antennas to a plurality of receive antennas.The adoption of MIMO has been most beneficial in wireless communicationsystems for use in environments having significant multipath scatteringpropagation. One such system is IEEE802.11n for use in home networkingAttempts have been made to utilize MIMO and spatial multiplexing in lineof sight environments having minimal scattering, which have generallybeen met with failure, in contrast to the use of cross polarizedcommunications. For example IEEE802.11n based Mesh networked nodesdeployed at streetlight elevation in outdoor environments oftenexperience very little benefit from the use of spatial multiplexing dueto the lack of a rich multipath propagation environment. Additionally,many of these deployments have limited range between adjacent mesh nodesdue to physical obstructions resulting in the attenuation of signallevels.

Radios and systems with MIMO capabilities intended for use in both nearline of sight (NLOS) and line of sight (LOS) environments are disclosedin U.S. patent application Ser. No. 13/212,036, now U.S. Pat. No.8,238,318, and Ser. No. 13/536,927, both of which are incorporatedherein by reference, and are referred to herein by the term “IntelligentBackhaul Radio” (IBR).

FIGS. 3A and 3B illustrate exemplary embodiments of the disclosed IBRs.In FIGS. 3A and 3B, the IBRs include interfaces 304A, interface bridge308A, MAC 312A, modem 324A, channel MUX 328A, RF 332A, which includesTx1 . . . TxM 336A and Rx1 . . . RxN 340A, IBR Antenna Array 348A(includes multiple antennas 352A), a Radio Link Controller (RLC) 356Aand a Radio Resource Controller (RRC) 360A. The IBR may optionallyinclude an “Intelligent Backhaul Management System” (or “IBMS”) agent370B as shown in FIG. 3B. It will be appreciated that the components andelements of the IBRs may vary from that illustrated in FIGS. 3A and 3B.

Embodiments of such intelligent backhaul radios, as disclosed in theforegoing references, include one or more demodulator cores within modem324A, wherein each demodulator core demodulates one or more receivesymbol streams to produce a respective receive data interface stream; aplurality of receive RF chains 340A within IBR RF 332A to convert from aplurality of receive RF signals from IBR Antenna Array 348A, to aplurality of respective receive chain output signals; a frequencyselective receive path channel multiplexer within IBR Channelmultiplexer 328A, interposed between the one or more demodulator coresand the plurality of receive RF chains, to produce the one or morereceive symbol streams provided to the one or more demodulator coresfrom the plurality of receive chain output signals; an IBR Antenna Array(348A) including: a plurality of directive gain antenna elements 352A;and one or more selectable RF connections that selectively couplecertain of the plurality of directive gain antenna elements to certainof the plurality of receive RF chains, wherein the number of directivegain antenna elements that can be selectively coupled to receive RFchains exceeds the number of receive RF chains that can accept receiveRF signals from the one or more selectable RF connections; and a radioresource controller, wherein the radio resource controller sets orcauses to be set the specific selective couplings between the certain ofthe plurality of directive gain antenna elements and the certain of theplurality of receive RF chains.

The intelligent backhaul radio may further include one or more modulatorcores within IBR Modem 324A, wherein each modulator core modulates arespective transmit data interface stream to produce one or moretransmit symbol streams; a plurality of transmit RF chains 336A withinIBR RF 332A, to convert from a plurality of transmit chain input signalsto a plurality of respective transmit RF signals; a transmit pathchannel multiplexer within IBR Channel MUX 328A, interposed between theone or more modulator cores and the plurality of transmit RF chains, toproduce the plurality of transmit chain input signals provided to theplurality of transmit RF chains from the one or more transmit symbolstreams; and, wherein the IBR Antenna Array 348A further includes aplurality of RF connections to couple at least certain of the pluralityof directive gain antenna elements to the plurality of transmit RFchains.

The primary responsibility of the RLC 356A in exemplary intelligentbackhaul radios is to set or cause to be set the current transmit“Modulation and Coding Scheme” (or “MCS”) and output power for eachactive link. For links that carry multiple transmit streams and usemultiple transmit chains and/or transmit antennas, the MCS and/or outputpower may be controlled separately for each transmit stream, chain, orantenna. In certain embodiments, the RLC operates based on feedback fromthe target receiver for a particular transmit stream, chain and/orantenna within a particular intelligent backhaul radio.

The intelligent backhaul radio may further include an intelligentbackhaul management system agent 370B that sets or causes to be setcertain policies relevant to the radio resource controller, wherein theintelligent backhaul management system agent exchanges information withother intelligent backhaul management system agents within otherintelligent backhaul radios or with one or more intelligent backhaulmanagement system servers.

FIG. 3C illustrates an exemplary embodiment of an IBR Antenna Array348A. FIG. 3C illustrates an antenna array having Q directive gainantennas 352A (i.e., where the number of antennas is greater than 1). InFIG. 3C, the IBR Antenna Array 348A includes an IBR RF Switch Fabric312C, RF interconnections 304C, a set of Front-ends 308C and thedirective gain antennas 352C. The RF interconnections 304C can be, forexample, circuit board traces and/or coaxial cables. The RFinterconnections 304C connect the IBR RF Switch Fabric 312C and the setof Front-ends 308C. Each Front-end 308C is associated with an individualdirective gain antenna 352A, numbered consecutively from 1 to Q.

FIG. 3D illustrates an exemplary embodiment of the Front-end circuit308C of the IBR Antenna Array 348A of FIG. 3C for the case of TDDoperation, and FIG. 3E illustrates an exemplary embodiment of theFront-end circuit 308C of the IBR Antenna Array 348A of FIG. 3C for thecase of FDD operation. The Front-end circuit 308C of FIG. 3E includes atransmit power amplifier PA 304D, a receive low noise amplifier LNA308D, SPDT switch 312D and band-select filter 316D. The Front-endcircuit 308C of FIG. 3E includes a transmit power amplifier PA 304E,receive low noise amplifier LNA 308E, and duplexer filter 312E. Thesecomponents of the Front-end circuit are substantially conventionalcomponents available in different form factors and performancecapabilities from multiple commercial vendors.

As shown in FIGS. 3D and 3E, each Front-end 308E also includes an“Enable” input 320D, 320E that causes substantially all active circuitryto power-down. Power-down techniques are well known. Power-down isadvantageous for IBRs in which not all of the antennas are utilized atall times. It will be appreciated that alternative embodiments of theIBR Antenna Array may not utilize the “Enable” input 320D, 320E orpower-down feature. Furthermore, for embodiments with antenna arrayswhere some antenna elements are used only for transmit or only forreceive, then certain Front-ends (not shown) may include only thetransmit or only the receive paths of FIGS. 3D and 3E as appropriate.

As described above, each Front-end (FE-q) corresponds to a particulardirective gain antenna 352A. Each antenna 352A has a directivity gainGq. For IBRs intended for fixed location street-level deployment withobstructed LOS between IBRs, whether in PTP or PMP configurations, eachdirective gain antenna 352A may use only moderate directivity comparedto antennas in conventional PTP systems at a comparable RF transmissionfrequency.

In the exemplary IBR Antenna Array 348A illustrated in FIGS. 3A, 3B and3C, the total number of individual antenna elements 352A, Q, is greaterthan or equal to the larger of the number of RF transmit chains 336A, M,and the number of RF receive chains 340A, N. In some embodiments, someor all of the antennas 352A may be split into pairs of polarizationdiverse antenna elements realized by either two separate feeds to anominally single radiating element or by a pair of separate orthogonallyoriented radiating elements. Such cross polarization antenna pairsenable either increased channel efficiency or enhanced signal diversityas described for the conventional PTP radio. The cross-polarizationantenna pairs as well as any non-polarized antennas are also spatiallydiverse with respect to each other. Additionally, the individual antennaelements may also be oriented in different directions to provide furtherchannel propagation path diversity.

Additional embodiments supporting MIMO technology in specificembodiments include the use so-called zero division duplexed (ZDD)intelligent backhaul radios (ZDD-IBR), as disclosed in U.S. patentapplication Ser. No. 13/609,156, which is additionally incorporatedherein by reference.

Embodiments of the ZDD systems provide for the operation of a IBRwherein the ZDD-IBR transmitter and receiver frequencies are close infrequency to each other so as to make the use of frequency divisionduplexing, as known in the art, impractical. Arrangements of ZDDoperation disclosed in the foregoing referenced application includeso-called “co-channel” embodiments wherein the transmit frequencychannels in use by a ZDD-IBR, and the receive frequencies are partiallyor entirely overlapped in the frequency spectrum. Additionally disclosedembodiments of ZDD-IBRs include so-called “co-band” ZDD operationwherein the channels of operation of the ZDD-IBR are not directlyoverlapped with the ZDD-IBR receive channels of operation, but are closeenough to each other so as to limit the performance the system. Forexample, at specific receiver and transmitter frequency channelseparation, the frequency selectivity of the channel selection filtersin an IBR transmitter and receiver chains may be insufficient to isolatethe receiver(s) from the transmitter signal(s) or associated noise anddistortion, resulting in significant de-sensitization of the IBR'sreceiver(s) performance at specific desired transmit power levels, without the use of disclosed ZDD techniques. Embodiments of the disclosedZDD-IBRs include the use of radio frequency, intermediate frequency andbase band cancelation of reference transmitter and interference signalsfrom the ZDD-IBR receivers in a MIMO configuration. Such disclosed ZDDtechniques utilize the estimation of the channels from the plurality ofIBR transmitters to the plurality of IBR receivers of the sameintelligent backhaul radio, and the adaptive filtering of the referencesignals based upon the channel estimates so as to allow the cancelationthe transmitter signals from the receivers utilizing such estimatedcancelation signals. Such ZDD techniques allow for increased isolationbetween the desired receive signals and the ZDD-IBR's transmitters invarious embodiments including MIMO configurations.

Referring now to FIG. 4A the MIMO channel matrix is depicted.Transceiver MIMO Station 405 is in communication with MIMO Station 410utilizing MIMO channel matrix (Eq.4-1) of FIG. 4B between the 2 stationsof FIG. 4A. In an example of a two-by-two MIMO system, two spatialstreams are utilized between the two MIMO stations. The channelpropagation matrix of Eq.4-1 is of order M by N comprised of M rows andN columns. A particular element of the channel propagation matrix,h_(mn), represents the frequency response of the wireless channel fromthe n^(th) transmitter to the m^(th) receiver. Therefore each element ofthe channel propagation matrix H is comprised of an individual complexnumber, if the channel is “frequency flat,” or a complex function offrequency, if the channel is “frequency selective,” which represents theamplitude and phase of the propagation channel between one transmitterand one receiver of MIMO Stations 405 and 410. Often, the channelpropagation matrix and the individual propagation coefficients arefrequency selective, meaning that the complex value of the coefficientsvary as a function of frequency as mentioned. In a rich, multipathscattering environment, as depicted in FIG. 4C, in which sufficientsignal strength reaches an intended receiver but is scattered amongstthe various structures between a particular MIMO transmitter and MIMOreceiver, the spatial distribution of the arriving signals is referredto as a rich multipath environment in which there is a significantangular scattering among the receiving signals at the intended receiver.

In order to separate the MIMO streams received at an intended receiver,such as MIMO Station 410 or MIMO Station 405, the channel propagationmatrix H must be determined, as known in the art. The process ofdetermining the channel propagation matrix is often performed utilizingpilot channels, preambles, and/or symbols or other known referenceinformation. Examples of prior art systems utilizing such techniquesinclude IEEE 802.11n, LTE, or HSPA, as well as various embodiments ofintelligent backhaul radios described in U.S. Pat. No. 8,238,818 andU.S. patent application Ser. Nos. 13/536,927 and 13/609,156, which arehereby incorporated by reference in their entireties.

In order for MIMO systems (including the foregoing mentioned MIMOsystems) to support a plurality of spatial MIMO streams, the order ofthe propagation matrix (referenced as Eq. 4-1) must exceed the desirednumber of streams. While this condition is necessary, it is notsufficient. The rank of the matrix must also exceed the number ofdesired spatial streams. The rank of a matrix is the maximum number oflinearly independent column vectors of the propagation matrix. Suchterminology is known in the art with respect to linear algebra. Thenumber of supportable MIMO streams must be less than or equal to therank of the channel propagation matrix. When the propagationcoefficients from multiple transmitters of a MIMO station to a pluralityof intended receive antennas are correlated, the number of linearlyindependent column vectors of the channel propagation matrix H isreduced and consequently the system supports fewer MIMO streams. Such acondition often occurs in environments where a small angular spread atthe desired intended receiver is present, such as is the case with aline-of-sight environment where the two MIMO stations are a significantdistance apart, such that the angular resolution of the receivingantennas at MIMO Station 410 is insufficient to resolve and separate thesignals transmitted from the plurality of transmitters at MIMO Station405. Such a condition is referred to as an ill-conditioned channelmatrix for the desired number of streams in the MIMO system, due to therank of the channel propagation matrix (i.e. the number of linearlyindependent column vectors) being less than the desired number of MIMOstreams between the two MIMO stations. The reason that the rank of thechannel propagation matrix is required to be greater than or equal tothe desired number of MIMO streams is related to how the individualstreams are separated from one another at the intended receiving MIMOstation. As is known in the art, the MIMO performance is quite sensitiveto the invertability of the channel propagation matrix. Suchinvertability, as previously mentioned, may be compromised by thereceiving antenna correlation, which may be caused by close antennaspacing or small angular spread at the intended MIMO receiver. Theline-of-sight condition between two MIMO stations may result in such asmall angular spread between the MIMO receivers, resulting in thechannel matrix being noninvertible or degenerate. Multipath fading,which often results from large angular spreads amongst individualpropagation proponents between two antennas, enriches the condition ofthe channel propagation matrix, making the individual column vectorslinearly independent and allowing the channel propagation matrix to beinvertible. The inversion of the channel propagation matrix results inweights (vectors), which are utilized with the desired receive signalsto separate the linear combination of transmitted streams intoindividual orthogonal streams, allowing for proper reception of eachindividual stream from spatially multiplexed composite informationstreams. In a line-of-sight environment, all of the column vectors ofthe channel propagation matrix H may be highly correlated, resulting ina matrix rank of 1 or very close to 1. Such a matrix is noninvertibleand ill-conditioned, resulting in the inability to support spatialmultiplexing and additional streams (other than by the use ofpolarization multiplexing, which provides for only 2 streams asdiscussed).

FIG. 4C illustrates an exemplary deployment of intelligent backhaulradios (IBRs). As shown in FIG. 4C, the IBRs 400C are deployable atstreet level with obstructions such as trees 404C, hills 408C, buildings412C, etc. between them. Embodiments of intelligent backhaul radios(IBRs) are discussed in U.S. Pat. No. 8,238,318, and co-pending U.S.patent application Ser. No. 13/536,927, the entities of which are herebyincorporated by reference. The IBRs 400C are also deployable inconfigurations that include point-to-multipoint (PMP), as shown in FIG.4C, as well as point-to-point (PTP). In other words, each IBR 400C maycommunicate with more than one other IBR 400C.

For 3G, and especially for 4^(th) Generation (4G), cellular networkinfrastructure is more commonly deployed using “microcells” or“picocells.” In this cellular network infrastructure, compact basestations (eNodeBs) 416C are situated outdoors at street level. When sucheNodeBs 416C are unable to connect locally to optical fiber or a copperwireline of sufficient data bandwidth, then a wireless connection to afiber “point of presence” (POP) requires obstructed LOS capabilities, asdescribed herein.

For example, as shown in FIG. 4C, the IBRs 400C include an AggregationEnd IBR (AE-IBR) and Remote End IBRs (RE-IBRs). The eNodeB 416C of theAE-IBR is typically connected locally to the core network via a fiberPOP 420C. The RE-IBRs and their associated eNodeBs 416C are typicallynot connected to the core network via a wireline connection; instead,the RE-IBRs are wirelessly connected to the core network via the AE-IBR.As shown in FIG. 4C, the wireless connection between the IBRs includeobstructions (i.e., there may be an obstructed LOS connection betweenthe RE-IBRs and the AE-IBR). Note that the Tall Building 412Csubstantially impedes the signal transmitted from RE-IBR 400C to AR-IBR400C. Additionally, in at least one example scenario, the tree (404C)provides unacceptable signal attenuation between an RE-IBR 400C and theAE-IBR 400C.

SUMMARY

The following summary of the invention is included in order to provide abasic understanding of some aspects and features of the invention. Thissummary is not an extensive overview of the invention and as such it isnot intended to particularly identify key or critical elements of theinvention or to delineate the scope of the invention. Its sole purposeis to present some concepts of the invention in a simplified form as aprelude to the more detailed description that is presented below.

Embodiments of the invention support a richer multipath environment orotherwise enhance the propagation matrix between either point-to-pointor point-to-multipoint radios. Embodiments of the invention provide adevice to increase the rank of the channel propagation matrix or toincrease the magnitude of the coefficients of the propagation matrixbetween two radios. Some embodiments of the invention are directed todevices to enhance the performance of either point-to-point orpoint-to-multipoint backhaul radios in one or both of range or of numberof supportable information streams. Further embodiments of the inventionare directed to devices to provide for flexibility in deploymentscenarios of either point-to-point or point-to-multipoint backhaulradios. Yet other embodiments of the invention are directed towardmethods for and implementations enabling the installation, provisioning,optimization, control, monitoring, and adaptation of such devices withina network of backhaul radios. Specific embodiments include wirelesscommunications links, and processes for communication and control. Someembodiments that provide common control communications between IBR andECHO devices and between ECHO devices and other ECHO devices, include anembedded wireless communication signal within the existing wirelesscommunications signals. Some embodiments utilize a direct sequencespread spectrum MODEM in one or more of the IBR and the ECHO devices,which allow for the transmission and reception of control channelsignals in the presence of ongoing IBR communications. Some embodimentsof the control channel signals provide a structure allowing for stream,channel, device or link specific control communications in a formatreferred to as a common control channel.

Yet other embodiments of the invention include methods and devices forthe measurement of RF parameters and the control of RF parameters of anRF repeater device for use with backhaul radio networks. Someembodiments utilize the control channel signal properties for theoptimization of various RF parameters in one or more of the IBR and ECHOdevices utilizing the control channel signal properties.

Additional embodiments of the invention provide for the structure andfunctioning of various ECHO devices, and associated communications andcontrol to and from other devices.

Embodiments of the invention solve the problem of a line-of-sightpropagation path, wherein the multipath environment may not be richenough to support more than two streams utilizing cross polarization ina MIMO radio configuration or more than a single stream when crosspolarization is not employed. Embodiments of the invention are able tosupport a single stream, or a plurality of MIMO streams in environmentswhere the propagation environment is such that the signal strength at areceiving radio is insufficient. Further embodiments of the inventionprovide methods for the operation of a wireless network innon-line-of-sight deployments for either point-to-point orpoint-to-multipoint backhaul radios to be able to support a “piecewise”line-of-sight, near line-of-sight, and/or non line-of-sight operation,wherein multiple segments of a particular link are utilized to provide apoint-to-point-like propagation environment, avoiding obstructions, suchas buildings or other geographical features that would otherwiseunacceptably impair a link between two radios. Such features mayseverely attenuate the signal propagating from a transmitter to anintended receiving device in such a backhaul radio configuration, insome embodiments. Additionally, embodiments of the invention supportone, two, or more streams, utilizing such MIMO configuration in aline-of-sight propagation environment, such as is present in directline-of-sight backhaul radio configurations or in piecewiseline-of-sight propagation configurations. Embodiments of the inventionenhance the wireless propagation environment, such that multipathpropagation (which is required for spatial multiplexing of multiplestreams) is sufficient, wherein otherwise such an environment would notallow for more than two streams, where two streams in suchconfigurations is generally supported by using cross polarization of twoorthogonally polarized transmitting antennas and two orthogonallypolarized receiving antennas (as discussed). Embodiments of theinvention also provide for a piecewise line-of-sight configuration,utilizing a middle node, providing an enhanced wireless propagationmatrix rank. Such a middle node between the two ends of either apoint-to-point or a point-to-multipoint wireless link may comprise acomplete demodulating radio including two transceivers with a bridgingor routing function between them. Other embodiments of a middle node mayutilize an RF repeater configuration, or a digital repeaterconfiguration, which provides for less functionality in some embodimentsof such a node but at a greatly reduced cost.

Embodiments of the invention include the use of ECHO devices withpoint-to-point and point-to-multipoint radios, such as an IBR, asdisclosed in U.S. patent application Ser. No. 13/212,036, now U.S. Pat.No. 8,238,318, and Ser. No. 13/536,927, both of which are incorporatedherein by reference. Additionally, further embodiments include the useof ECHO devices with so-called zero division duplexed (ZDD) intelligentbackhaul radios (ZDD-IBR), as disclosed in U.S. patent application Ser.No. 13/609,156.

According to an aspect of the invention, a multiple input multipleoutput (MIMO) wireless communication system is disclosed that includes afirst radio for transmission of a plurality of first information streamshaving one or more associated embedded first control signals; a secondradio for reception of the plurality of first information streams andreception of one or more embedded second control signals respectivelyassociated with one or more of the plurality of first informationstreams; a repeater device for repeating one or more of the plurality offirst information streams, wherein the repeater device further includesone or more of each of: a channel filter for channel filtering a signalcomprising at least one of the plurality of first information streamsand at least one of the one or more associated embedded first controlsignals; a detector for performing detection of at least one of the oneor more associated first embedded control signals; a repeater devicecontroller for enabling one or more transmitters of the repeater devicebased upon the detection; a demodulator for demodulating at least one ofthe associated first embedded control signals to determine associatedfirst control information; a modulator for generating one or more secondcontrol signals; a coupler for combining the one or more second controlsignals respectively with the signal comprising the one or more firstinformation streams to produce a composite signal comprising the one ormore second embedded control signals respectively associated with atleast one of the one or more first information streams; a transmitterfor the transmission of the composite signal; wherein the second radiofurther demodulates the one or more second embedded control signals todetermine second control information, and communicates informationwithin the second control information to the first radio; and whereinperformance of the MIMO wireless communication system is enhanced basedupon adjustment of parameters associated with one or more of: therepeater device, based upon information within the first controlinformation; and, the first radio, based upon information within thesecond control information.

The one or more associated embedded first control signals may eachinclude a signature signal. A particular signature signal may be uniqueto one of the one or more associated first information streams.

The particular signature signal may be orthogonal to at least one othersignature signal associated with another first information stream of theplurality of first information streams.

The repeater device may utilize the information within the first controlinformation to adjust the parameters associated with the repeaterdevice.

In one embodiment, the repeating is only performed following detectionof at least one of the one or more associated embedded first controlsignals.

The enhancement of the performance of the MIMO wireless communicationsystem may include reducing a receive signal level difference between atleast two of the plurality of the first information streams at thesecond radio.

The adjustment of parameters may set a signal level of one of theplurality of the first information streams at the repeater devicerelative to signal levels of one or more of the other first informationstreams of the plurality of first information streams to be comparablewith a predetermined ratio.

The parameters may be radio frequency (RF) parameters associated withphased array weights or settings for the repeater device and may berelated to at least two of the following: a first receiver signalassociated with the repeater device, a second receiver signal associatedwith the repeater device, a first transmitter signal associated with therepeater device, and a second transmitter signal associated with therepeater device.

The parameters may be associated with digital transmit beam formerweights or settings for the first radio.

The adjustment of parameters associated with the first radio may set thesignal level of one of the plurality of the first information streams atthe repeater device.

The adjustment of parameters associated with the repeater device may setthe signal level of one of the plurality of the first informationstreams detected at the second radio device.

The repeater device may further include: a plurality of receive antennastructures coupled to a respective plurality of low noise amplifiers(LNAs) to provide a respective plurality of LNA output receive signals;a plurality of receive chains respectively coupled to the plurality ofLNAs to receive the respective plurality of LNA output receive signalsand to provide a respective plurality of receive chain output receivesignals; a plurality of intermediate frequency (IF) couplers comprisinga respective plurality of the couplers, the plurality of IF couplersrespectively coupled to the plurality of receive chains to receive therespective receive chain output receive signals and to provide arespective plurality of IF coupler output receive signals and arespective plurality of IF coupler Modem receive signals; a plurality offrequency translating feedback cancellers respectively coupled to theplurality of IF couplers to respectively receive the IF coupler outputreceive signals and to provide one or more frequency translatingfeedback canceller RF output signals; a plurality of repeatertransmitters comprising the one or more transmitters, the plurality ofrepeater transmitters each respectively coupled to the plurality offrequency translating feedback cancellers to receive a respectivefrequency translating feedback canceller RF output signal and totransmit the composite signal; wherein the repeater device includes oneor more repeater device Modems, and wherein one or more of the one ormore repeater device Modems further include at least one Embedded LinkProcessor, one or more of the one or more repeater device Modems coupledto one or more of the plurality of IF couplers to receive one or more IFModem receive signals, and one or more of the one or more repeaterdevice Modems further includes the detector for performing detection ofat least one of the one or more associated first embedded controlsignals; wherein the repeater device controller is coupled to the one ormore repeater device Modems to exchange information with and providecontrol to the one or more repeater device Modems and to further providecontrol associated with the parameters, wherein the parameters areassociated with the repeater device.

One or more of the outputs of one or more of the plurality of frequencytranslating feedback cancellers may be further coupled to an RF combinerinterposed between at least one of the LNAs and the respective receivechains.

One of the one or more channel filters may be respectively interposedbetween the receive chains and the plurality of IF couplers.

The one or more of the one or more repeater device Modems may furtherinclude a detector for performing detection of at least one of theassociated second embedded control signals to determine second controlinformation, the second control information being utilized to performadjustment of parameters associated with the repeater device or thefirst radio device.

The receive signal may include at least one of the following: an LNAoutput receive signal; a receive chain output receive signal; an IFcoupler output receive signal; and IF coupler Modem receive signal.

According to another aspect of the invention, a multiple input multipleoutput (MIMO) wireless communication system is disclosed that includes:a first radio for transmission of a plurality of first informationstreams each having an associated embedded first control signal; asecond radio for reception of the plurality of first informationstreams; a repeater device for repeating one or more of the plurality offirst information streams, wherein the repeater device further includesone or more of each of: a channel filter for channel filtering a signalcomprising at least one of the plurality of first information streamsand at least one of the one or more associated embedded first controlsignals; a detector for performing detection of at least one of the oneor more associated first embedded control signals; a repeater devicecontroller for enabling one or more transmitters of the repeater devicebased upon the detection; a demodulator for demodulating at least one ofthe associated first embedded control signals to determine associatedfirst control information; a transmitter for the transmission of thecomposite signal comprising the at least one of one or more firstinformation streams and the respectively associated one or more secondembedded control signals; wherein the performance of the MIMO wirelesscommunication system is enhanced based upon adjustment of parametersassociated with the repeater device and based upon information withinthe first control information.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more examples ofembodiments and, together with the description of example embodiments,serve to explain the principles and implementations of the embodiments.

FIG. 1 is an illustration of conventional point-to-point (PTP) radiosdeployed for cellular base station backhaul with unobstructed line ofsight (LOS).

FIG. 2A is a block diagram of a conventional PTP radio for Time DivisionDuplex (TDD).

FIG. 2B is a block diagram of a conventional PTP radio for FrequencyDivision Duplex (FDD).

FIG. 3A is an exemplary block diagram of an IBR.

FIG. 3B is an alternative exemplary block diagram of an IBR.

FIG. 3C is an exemplary block diagram of an IBR antenna array.

FIG. 3D is an exemplary block diagram of a front-end unit for TDDoperation of an IBR.

FIG. 3E is an exemplary block diagram of a front-end unit for FDDoperation of an IBR.

FIG. 4A is an illustration of the MIMO station propagation matrixelements.

FIG. 4B illustrates the MIMO channel propagation matrix equation andassociated terminology.

FIG. 4C is an exemplary illustration of intelligent backhaul radios(IBRs) deployed for cellular base station backhaul with obstructed LOS.

FIG. 5A is an exemplary block diagram of an IBR including an EmbeddedLink Processor (ELP).

FIG. 5B is an exemplary block diagram of an Embedded Link Processor(ELP).

FIG. 5C is an exemplary block diagram of an embedded control channelmodem.

FIG. 6A is an illustration of IBR radios deployed in a point-to-point(PTP) or point-to-multipoint (PTMP) configuration utilizing ECHO relaysdeployed for cellular base station backhaul according to certainembodiments of the invention.

FIG. 6B is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing an ECHO relay with an obstructed directpropagation path, and bidirectional ECHO links.

FIG. 6C is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with anobstructed direct propagation path, and bidirectional ECHO links.

FIG. 6D is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with anobstructed direct propagation path, and unidirectional ECHO links.

FIG. 6E is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with a line ofsight (LOS) direct propagation path, and bidirectional ECHO links.

FIG. 6F is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with a nearline of sight (NLOS) direct propagation path utilizing a unidirectionallink, and unidirectional ECHO links.

FIG. 7 illustrates the MIMO channel propagation matrix equation forpiece wise propagation segments utilizing ECHO Relays.

FIG. 8A is a block diagram illustrating an exemplary single stream ECHORelay according to one embodiment of the invention.

FIG. 8B is a block diagram illustrating an exemplary single stream ECHORelay including a Frequency Translating Feedback Canceller according toone embodiment of the invention.

FIG. 8C is a block diagram illustrating an exemplary FrequencyTranslating Feedback Canceller according to one embodiment of theinvention.

FIG. 8D is a block diagram illustrating an alternative exemplaryFrequency Translating Feedback Canceller according to one embodiment ofthe invention.

FIG. 8E is a block diagram illustrating an exemplary dual stream ECHORelay including Frequency Translating Feedback Cancellers according toone embodiment of the invention.

FIG. 8F is a block diagram illustrating an exemplary dual stream ECHORelay including Frequency Translating Feedback Cancellers utilizinginternal feedback according to one embodiment of the invention.

FIG. 8G is a block diagram illustrating an exemplary FDD/ZDDconfiguration of two dual stream ECHO Relays according to embodiments ofthe invention.

FIG. 8H is a block diagram illustrating an exemplary TDD configurationof a dual stream ECHO Relay according to embodiments of the invention.

FIG. 8I is an exemplary block diagram of an ECHO Modem including anEmbedded Link Processor (ELP).

FIG. 9A is a flow diagram of the controller for an ECHO Relay accordingto one embodiment of the invention.

FIG. 9B is a message sequence chart for a network of IBR radios and anECHO Relay deployed in a point-to-point (PTP) configuration.

FIG. 10 is a block diagram of an ECHO antenna array according to oneembodiment of the invention

FIG. 11 is a block diagram of an ECHO antenna array according to oneembodiment of the invention.

FIG. 12 is an exemplary diagram of a dual-polarity, two-port patchantenna element including feed and grounding points.

FIG. 13A is an exemplary diagram of a front view of a dual-polarity, twoport, patch antenna array.

FIG. 13B is an exemplary diagram of a side view of a dual-polarity, twoport, patch antenna array.

FIG. 14 is an illustration of an ECHO device according to one embodimentof the invention.

DETAILED DESCRIPTION

Referring now to FIG. 5A, an embodiment of an IBR including an EmbeddedLink Processor (ELP) is depicted. A number of the blocks common withFIG. 3B are shown, whose functioning is generally described associatedwith the foregoing description. Relative to FIG. 3B, FIG. 5A providesfor a modified IBR MAC 512A, and an additional block referred to as anEmbedded Link Processor (ELP) 500.

Embodiments of IBR MAC 512A generally incorporate the functionality ofthe various embodiments of IBR MAC 312A. Some Embodiments of IBR MAC512A additionally include MAC processing supporting the optimization ofthe wireless links utilizing ECHO devices. Additionally some embodimentsof IBR MAC 512A support peer to peer and communications with otherdevices (e.g. ECHO devices) utilizing an embedded control channel forthe transfer of control information.

Embodiments of the Embedded Link Processor (ELP) 500 provide for thereception and insertion of an additional wireless communications channelreferred to as an embedded control channel in specific embodiments.Associated with IBR transmission, the Embedded Link Processor (ELP)receives transmit symbol streams (1 . . . K) from IBR Modem 324A andprovides the same transmit symbol streams (1 . . . K) to the IBR ChannelMUX 328A with additional embedded control channels added to theindividual streams, if such processing is enabled. In some embodimentswhere embedded control channels are not actively associated with anyspecific transmit symbol stream, the transmit symbol streams are passedto their respective output streams with no addition of embedded controlchannel signal. Embodiments of the ELP may provide for a unique embeddedcontrol channel to be added to each of the respective transmit symbolstreams. In other embodiments the ELP may provide for the components ofthe control channel, or the control channel in its entirety, to be addedcommonly to all transmit symbol stream in a related fashion.

In one exemplary embodiment utilizing a common control channelstructure, a direct sequence spread spectrum pilot signal utilizing afirst orthogonal code is added commonly to all streams processed fortransmission by the ELP. Additionally, in the instant embodiment, eachindividual stream receives a respective second copy of the directsequence spread spectrum (DSSS) pilot signal, but modulated with adiffering orthogonal code respectively associated with the individualtransmit symbol streams. Such modulation may be accomplished usingmodulo 2 additions, or bi-phase modulation as known in the art. Theindividual orthogonal codes may additionally be modulated by informationbits in the form of the IBR_ELP_Data transmit data interface stream,resulting in an embedded control sub-channel symbol stream. One suchreference teaching DSSS and CDMA modulation and demodulation techniquesis CDMA: Principles of Spread Spectrum Communications, by Andrew J.Viterbi (Addison Wesley Longman, Inc., ISBN: 0-201-63374-1). Someembodiments of the embedded control channel having a specific structureutilizing multiple sub-channels is referred to as a common controlchannel. The use of either term in specific instances should not beconsidered limiting, and in some cases the terms are utilizedinterchangeably.

Embodiments of the Embedded Link Processor (ELP) 500 further provide forthe reception and demodulation of embedded control channels insertedinto one or more transmitted symbol streams by other devices, such as anECHO device. Associated with IBR reception, the Embedded Link Processor500 receives receive symbol streams (1 . . . L) from IBR Channel MUX328A and provides the same transmit symbol streams (1 . . . . L) to theIBR Modem 324A, with the detection and or demodulation of any associatedembedded control channels within the individual streams, if suchprocessing is enabled. The resulting demodulated data from the embeddedcontrol channels is provided by to the IBR MAC 512A by the ELP 500 asIBR_ELP_Data. Embodiments of the ELP may provide for a unique embeddedcontrol channel to be received and demodulated and associated with eachof the respective receive symbol streams. In other embodiments the ELPmay provide for the components of the control channel or the controlchannel in its entirety to be detected and demodulated commonly from allreceive symbol streams.

In alternative embodiments, with appropriate interfaces, the ELP may beplaced between the IBR Channel Mux 328A and the IBR RF 332A so as toallow for a single embedded control channel on a per transmit or receivechannel basis rather than on per symbol stream basis.

In yet further alternative embodiments, a similar per channel embeddedcontrol channel result may be obtained utilizing the ELP placement asshown in FIG. 5A utilizing amplitude and phase weightings so as to causethe IBR Channel MUX to achieve the intended result. Such combinations ofIBR Channel MUX processing with coordinated ELP processing further allowfor additional control of capabilities of mapping specific embeddedcontrol streams with specific transmit or receive channels associatedwith the IBR RF 332A.

FIG. 5B is an exemplary block diagram of an embodiment of the EmbeddedLink Processor (ELP) 500. The ELP controller provides for interfacingthe ELP_Data, RLP, RRC and/or RLC with the ECCM_Data-(1 . . . KL) andECCM_Ctrl-(1 . . . KL) communication with the individual EmbeddedControl Channel Modems (510B-1 . . . 510B-KL). Such interfaces allow forthe interchange of data, including and control information with theindividual modems. For example the relative signal level and timing ofthe individual per stream control channels and sub-channels to beembedded within transmit symbol streams may be set utilizing the controlinformation contained within the ECCM_Ctrl-kl signals (where kl varieslinearly from 1 to KL). Additionally the correlated signal level of anembedded control channel or sub-channel, the received signal levelindication of all the signals, the timing information of the receivedsignals may be additionally communicated from the individual ECCM Modemsto the ELP Controller 520B, and to the RLP, ELP_Data, and RRCsubsequently. It should be understood that the ELP_Data signal of FIG.5B corresponds to the IBR_ELP_Data signal of FIG. 5A. It will beappreciated that the ELP will be described in further detail hereinafterwith reference to ECHO devices, and, accordingly, the naming within FIG.5B is generic for purposes of the present discussion.

Additionally, the DRx-kl signals (where kl varies from 1 to KL) providefor digitally sampled signals associated with the 1 to L receive symbolstreams, in some embodiments. The DRx_Out-kl signals (where kl variesfrom 1 to KL) are respectively coupled to DRx-kl, to provide for a passthrough operation of the respective DRx-kl signals, for example when anELP is utilized within an IBR. Such a pass through coupling, in someembodiments, allows for the coupling of the receive symbol streams fromthe IBR Channel MUX 238A to the IMR Modem 324A. In some alternativeembodiments where the ELP is utilized within a repeater device, suchDRx_Out-kl signals may not be utilized by the repeater device and maynot be depicted as external ports to the ELP in such embodiments.

The DTx_In-kl and DTx_Out-kl signals (where kl varies from 1 to KL)provide for a digitally sampled signals associated with the 1 to Ktransmit symbol streams respectively input and output from ELP 500, insome embodiments. An individual Embedded Control Channel Modem 510B-kl,provides a modulated control channel (MTx-kl) to a respective Adder514B-kl, which in sums MTx-kl with the input transmit symbol streamDTx_In-kl. Adder 514B-kl in turn provides the Embedded Control ChannelSignal DTx_Out. In embodiments where no input to the DTx_In-kl isprovided, the MTx-kl signal is provided directly as DTx-kl.

Note that KL need not be equal to either K or L. In some embodimentswhere there is a one to one correspondence between transmit symbolstreams and embedded control channels (or sub-channels in a commoncontrol channel structure), KL must be equal to or greater than K. Incases where KL (the number of ECCMs) exceeds K (the number of transmitsymbol streams) the excess ECCMs may not be utilized for transmission,or may be used for other purposes. One such purpose would be for usededicated to a transmit channel, such as might be used with a singlehigh gain antenna panel for example.

Further, when there is a one to one correspondence between the number ofreceive symbol streams and the number of embedded control channelsassociated with these streams, KL (number of ECCMs) must be equal to orexceed L (number of receive symbol streams). In the case where KLexceeds L, a number of the ECCMs may remain unused for reception ofembedded control channels, or may be utilized for other purposes such asreceiving embedded control channels from individual receive channels.

FIG. 5C is an exemplary block diagram of an embodiment of an embeddedcontrol channel modem 510B-kl. Digitally sampled receive symbol streamDRx-kl is coupled to Embedded Control Channel Detector/Synchronizerblock 570C, which preforms timing synchronization with the DSSS signalswithin the input signal, and detects the presence and associated signallevels (in uncorrelated and correlated levels for example, Io, Ec, Es,Ec/Io and/or, Es/Io), and associated timing information and provides oneor more of the determined values to the Modem Timing Controller 550C.The Modem Timing Controller, in one embodiment, utilizes the timing andreceived Ec/Io information to trigger the demodulation and ortransmission of embedded control signals respectively associated withthe Digital Demodulator 560C and the Digital Modulator 580C. Thedigitally sampled receive symbol stream DRx-kl is additionally coupledto the Digital Demodulator 560C, which upon receiving ECCM_Ctrlconfiguration information, and timing information from the Modem TimingController dispreads and demodulates the DSSS signals associated withthe Embedded Control Channel and any associated pilot, and datasub-channels. The ECCM_Ctrl configuration information, in specificembodiments, may contain a specific PN code, Gold code, or other code tobe utilized for spreading and dispreading in the ECCM 510B for use inDigital Demodulator 560C and Digital Modulator 580C. Additionally, theECCM_Ctrl may contain the identity of values of specific orthogonalcodes for use with specific sub-channels of a common control channelstructure. Such orthogonal codes may include Walsh Codes, CAZAC Codes,Zadoff-Chu codes and the like. Further, the specific codes may bedesignated for use with a pilot channel utilized for synchronization andas a phase and amplitude reference for demodulation, and other codes maybe designated for use with specific data sub-channels carrying BPSKmodulated data in one example embodiment. Referring to FIG. 5C, DigitalModulator 580C provides a modulated control channel signal MTx-kl, uponreceiving the mentioned configuration information from the ECCM_Ctrl,the ECCM_Data to be transmitted, and the timing from the Modem TimingController 550C. Either, or both of the Digital Modulator 580C and theDigital Demodulator 560C may be disabled utilizing the ECCM_Ctrl signal.

As mentioned previously, such DSSS and CDMA transmission and receptionapproaches and structures are well known in the art including asutilized in the downlink of IS-95, W-CDMA, CDMA-2000 and the like.Further aspects of such art is disclosed in the previously referencesbook CDMA: Principles of Spread Spectrum Communications, by Andrew J.Viterbi (Addison Wesley Longman, Inc., ISBN: 0-201-63374-1).

FIG. 6A is an illustration of IBR radios deployed in both point-to-point(PTP) and point-to-multipoint (PTMP) configurations, utilizing ECHOrelays deployed for remote backhaul (i.e. of a cellular base station),according to embodiments of the invention. A plurality of IntelligentBackhaul Radios 1 through M, as well as embodiments of the currentinvention, referred to as ECHO (Enhanced CHannel propagation matrixOrder and rank) relays are depicted. FIG. 6A shows a topology of thecombination of IBRs and ECHOS, which allow for the enhancement ofchannel propagation matrices between two or more IBRs, utilizing one ormore ECHO devices. The nomenclature of the figure describes theindividual propagation channels between each of the IBRs and ECHOsdepicted in the figure. As an example, the propagation channel betweenIBR-1 and IBR-m (6A-II-1m) may be referred to as IBR-IBR(1,m). Thepropagation channel between an IBR and an ECHO device, such as depictedin Link 6A-IE-11 is referred to using the nomenclature IBR-ECHO (1,1). Athird type of link between two ECHO devices is depicted in Link6A-EE-1n, as ECHO-ECHO (1,n). Embodiments of the use of ECHO devices inthe current invention, may utilize one or a plurality of links betweenindividual nodes. In various embodiments of point-to-point andpoint-to-multipoint links, for instance between IBR-1, IBR-m, and IBR-M,one or more links may be utilized, including in one embodiment, a directline-of-sight link 6A-II-1M, while in other embodiments, a line-of-sightlink may not be used at all, while in still other embodiments theline-of-sight link may be used in combination with piecewise propagationlinks via an ECHO device. In specific embodiments, one or bothpoint-to-point and point-to-multipoint configurations of IBRs utilizingECHO devices are disclosed. In general the disclosed point-to-pointembodiments are also contemplated and disclosed for use withpoint-to-multipoint links if not specifically stated. In someembodiments, such omissions are for the purpose of the clarity of thedisclosure. In yet further embodiments, the full duplex communicationsbetween two IBRs may utilize the same or different configurations in onedirection, relative to the return path between two IBRs. For instance, apath from IBR-1, desiring a rich channel matrix, may employ both thedirect line of sight path (or near line of sight path) to IBR-M, as wellas the path utilizing ECHO-1, such that a richer angular spread iscreated at IBR-M while the return path from IBR-M to IBR-1 may utilizeonly the line-of-sight path or may utilize any combination of ECHOdevices which may or may not include the line-of-sight path returning toIBR-1. In such a configuration, the path from IBR-1 to IBR-M may be timemultiplexed with the return path from IBR-M to IBR-1 in a (TDD) timedivision duplexed mode, or may be (FDD) frequency duplexed or (ZDD) zerodivision duplexed with the return path. Additionally two or more ECHOdevices may be used to combine a serial propagation path from IBR-1 toIBR-M, utilizing ECHO-1, ECHO-N, and/or ECHO-n to IBR-M. The use ofdiffering configurations between the propagation in one directionrelative to the other direction, between two IBRs, may be desirable dueto the required data rate of the links or may be due to the frequencyselectivity between the two links or other factors such as localizedinterference.

FIG. 6B is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing an ECHO relay with an obstructed directpropagation path, and bidirectional ECHO links.

FIG. 6B depicts a specific configuration showing a line-of-sight pathbetween two IBRs wherein the signal strength between the two IBRs isinsufficient to support a propagation path enabling line-of-sightcommunications between IBR-6B-1 and IBR-6B-2, due to the obstruction ofthe line-of-sight path by tall buildings (6B-30). The inability for theline-of-sight path between the two IBRs poses a significant problemwhich is resolved by utilizing ECHO-6B-1 to provide for a piece-wiseline-of-sight propagation between the IBRs. Such a piece-wisepropagation is supported by IBR-ECHO (1, 1) and IBR-ECHO (2, 1) viaECHO-6B-1. Each of the propagation segments includes an individualline-of-sight propagation environment, allowing for two streams to besupported by polarization of the transmitting and receiving antennas oran alternative embodiment utilizing MIMO propagation relying on themultipath of the propagation channels. Such a piece-wise propagationpath may be supported utilizing time division duplexed, frequencydivision duplexed, or zero division duplexed repeating at the ECHOdevice. However, in environments where the individual propagationsegments are line-of-sight and no multipath exists, the same degeneratechannel matrix condition for MIMO communications may exist. In suchenvironments, only two streams utilizing orthogonal polarizationsbetween the antennas of the receiving and transmitting stations of eachpiece-wise segment may be utilized, resulting in the support of twostreams only. In yet other embodiments, where polarized antennas are notutilized, only a single stream may be supported when the piece-wiseline-of-sight segments are utilized.

FIG. 6C is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with anobstructed direct propagation path, and bidirectional ECHO links.

FIG. 6C depicts, in some embodiments, the problem of piece-wiseline-of-sight propagation addressed by utilizing a plurality of ECHOdevices. Such a configuration allows for a richer multipath environment,created by the plurality of line-of-sight segments propagated by theplurality of ECHO devices. In such a configuration, up to four streamsmay be supported by the piece-wise line-of-sight segments, utilizingpolarization on each of the individual line-of-sight segments, allowingfor two streams to be relayed by each ECHO device between each IBR. Aswith FIG. 6B, the direct line-of-sight propagation between IBR-6C-1 andIBR-6C-2, depicted in FIG. 6C, is obstructed by the tall buildings(6B-30). Bidirectional communications may be supported in the currentembodiment with frequency division duplexing, time division duplexing,or zero division duplexing depending upon the configurations of the IBRsand the ECHO devices. Additionally, a plurality of ECHO devices may beco-located at ECHO-6C-1 and ECHO-6C-2, each of which are unidirectionalrelaying devices, wherein each of the depicted ECHO-6C-1 and ECHO-6C-2include a plurality of ECHO devices, as depicted in further detailbelow. Such embodiments allow for the support of frequency divisionduplexing, as well as time division duplexing or zero divisionduplexing, bidirectional communications between the two IBRs. It shouldbe recognized that embodiments disclosed herein may support the generaluse of TDD, FDD, or ZDD (Zero Division Duplex) communications betweenendpoint IBRs and the various configurations of ECHO devices utilized tosupport them should be considered as disclosed throughout the variousembodiments as depicted in the current and subsequent figures showingdeployment scenarios of IBRs and their link enhancement utilizing ECHOdevices.

FIG. 6D is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with anobstructed direct propagation path, and unidirectional ECHO links.

FIG. 6D depicts a similar configuration to the previous deployment;however, rather than each of the ECHO devices being bidirectional asdescribed, each ECHO device is unidirectionally allowing for thedeployment of differing propagation paths utilizing piece-wiseline-of-sight or other embodied MIMO channels between IBR-6D-1 toIBR-6D-2, wherein the forward path from IBR-6D-1 to IBR-6D-2 utilizesECHO-6D-1 via piece-wise propagation path 6D-1E-11 (IBR-ECHO (1,1)),utilizing ECHO device ECHO-6D-1, and piece-wise propagation path6D-IE-21 (IBR-ECHO (2,1)) to IBR 6D-2. The return path from IBR-6D-2 toIBR-6D-1 utilizes ECHO device ECHO-6D-2 via piece-wise propagation paths6D-IE-22 (IBR-ECHO (2,2)), and 6D-IE-12 (IBR-ECHO (1,2)). As can beseen, the different unidirectional ECHO devices each support either theforward path or the reverse path between the two devices. These two ECHOdevices may be physically co-located or may be physically separated. Inthe case where they are physically separated there may be someadvantage, in specific embodiments, in supporting significant angulardifferences in propagation between the piece-wise propagation paths atthe transmitting and receiving IBRs, which may provide for theopportunity for further performance enhancement utilizing transmitterand receiver beam forming techniques within the IBRs to provide foradditional isolation and performance relative to the forward path andreverse path between the two IBRs. Further, each of the unidirectionalpropagation paths may be comprised of two spatial streams enabled bypolarized antennas in piece-wise line-of-sight environments or inmultipath rich environments, enabled by individual spatially multiplexedstreams which may support one, two or more propagated streams betweeneach piece-wise propagation path. The direct line-of-sight path in thecurrent embodiment is also obstructed, preventing the directcommunication without the use of an ECHO device between the IBRs.Alternative embodiments may have a weak or a direct line-of-sightpropagation path between the two IBRs which may be used in conjunctionwith the plurality of ECHO devices, the ECHO devices beingunidirectional or bidirectional.

FIG. 6E is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with a line ofsight (LOS) direct propagation path, and bidirectional ECHO links.

FIG. 6E, depicts, in one embodiment, a deployment wherein theline-of-sight path between IBR-6E-1 and IBR-6E-2 provides for a directcommunication between the two IBRs. This communication may bebidirectional in some embodiments and may be unidirectional in otherembodiments. The supporting of the two unidirectional ECHO devicesoperate in a manner similar to that described with reference to FIG. 6D,except that the two unidirectional ECHO devices are used in combinationwith the direct line-of-sight propagation path in one or both theforward and reverse directions. One key consideration when a pluralityof propagation paths between a transmitting and receiving IBR arepresent and at least one of those paths utilize an ECHO device, therelative magnitude of the propagation path (i.e., the path loss betweenthe two IBRs for that specific path) is of particular importance. If therelative magnitude of the individual propagation paths is too large, theperformance of the spatial multiplexing amongst those paths may becompromised. A first path being received at a receiving IBR, which issufficiently larger than the magnitude of the signal from a second path,each path supporting an individual spatial stream, dominates the secondpath, preventing the de-multiplexing and isolation of the individualstreams and compromising performance. For every decibel (dB) ofincreased dynamic range between the two paths, an equal increase in theoverall stream isolation is required so as to support the data rates ofthe individual streams, which would otherwise be possible. As a result,adjusting the gains of paths through ECHO devices so as to minimize thedynamic range of individual receive signal levels is desirable. Inembodiments of the invention, such an adjustment may be supportedutilizing control communications amongst the IBRs and the ECHO devices.In some embodiments where the communications are bidirectional, ECHOdevices may communicate with the transmitting IBR directly or maycommunicate with another device, which then communicates with thetransmitting IBR, as an example. In other embodiments where the ECHOdevice is unidirectional, the ECHO device may transmit information toanother device which may then process or simply relay the information tothe original transmitting IBR utilizing the return link between theIBR-to-IBR, point-to-point links. Embodiments describing suchcommunication are disclosed later in this specification.

FIG. 6F is an illustration of IBR radios deployed in a point-to-point(PTP) configuration utilizing a plurality of ECHO relays with a nearline of sight (nLOS) direct propagation path utilizing a unidirectionallink, and unidirectional ECHO links.

FIG. 6F depicts the example scenario where the direct path betweenIBR-6F-2 and to IBR-6F-1 is near line of sight and is utilized withsignal propagating through and scattering amongst Tree 6F-1 via Link6F-II-21, comprising Link IBR-IBR (2,1). While this propagation pathsupports communications from IBR-6F-2 to IBR-6F-1, the path fromIBR-6F-1 to IBR-6E-2 does not use the near line-of-sight Path 6F-II-21.This communication channel is supported utilizing two ECHO devices,ECHO-6F-1 and ECHO-6F-2. The forward path from IBR-6F-1 via the ECHOdevices is capable of producing a plurality of piecewise line-of-sightlinks wherein propagation from IBR-6F-1 to ECHO-6F-1 via Link 6F-IE-11supports two streams in the current embodiment utilizing orthogonalpolarizations of the transmitting and receiving antennas. The sameconfiguration is supported from ECHO-6F-1 to IBR-6E-2 via PropagationPath 6F-IE-21 utilizing Link IBR-ECHO (2, 1). Likewise as additional twopaths may be supported by piecewise line-of-sight link from IBR-6F-1 toIBR-6F-2 utilizing ECHO-6F-2 and piecewise line-of-sight Links 6F-IE-12(IBR-ECHO (1, 2)), and Link 6F-IE-22 (IBR-ECHO (2, 2)). Each piecewiseline-of-sight link utilizing unidirectional ECHO devices supports one ortwo streams utilizing orthogonal polarizations, resulting in fourstreams in a piecewise line-of-sight configuration in some embodiments.

FIG. 7 illustrates the MIMO channel propagation matrix equation forpiece wise propagation segments utilizing ECHO Relays.

FIG. 7 depicts the individual elements of the channel propagation matrixof Eq. 7-1 in the context of utilization of the ECHO devices. Eq. 7-1depicts the channel matrix elements having the individual propagationsegments of Eq. 7-2. Each individual propagation segment of Eq. 7-2 isrepresented by L_(s). Each individual propagation channel from then^(th) transmitter to the m^(th) receiver is depicted by the product ofS(k,m,n) individual propagation segments together comprising onepropagation path, where there are s=1 to S (k,m,n) propagation segments.The individual element of the propagation channel matrix h_(m,n) is thesummation of K (where k=1 to K) propagation paths.

L_(s) designates an individual propagation segment where L_(s)=h_(s), ifthe individual propagation segment s is equal to S (k, m, n), indicatingthat the propagation segment terminates with the n^(th) receiver on anIBR. Otherwise L_(s)=h_(s)×g_(Es), ifs is less than S (k,m,n) indicatingthat the propagation segment terminates with an ECHO device where h_(s)represents the frequency response of the wireless propagation channel ofthe s^(th) segment and g_(Es) represents the frequency response of thes^(th) ECHO device (including gain). Thus Eq. 7-2 describes thesummation of K propagation paths, each having the products of individualpropagation segments comprising a cumulative frequency selective channelresponse between the transmitter and the nth receiver between two IBRs.As may be appreciated, the adjusting of g_(Es) for each propagationsegment contained within a particular channel propagation matrix elementof Eq. 7-2 and relative to other channel propagation matrix elements ofEq. 7-1 allows for the dynamic range of the magnitude of an individualchannel propagation matrix element relative to the other channelpropagation elements to be managed actively through dynamic adjustmentof the individual g_(Es), for each segment. As a result an optimal setof gain settings for the segments may be chosen such that an appropriatereceived signal level for each individual stream is received at thereceiving destination IBR from the transmitting source IBR incombination of direct paths between the two IBRs as well as pathsutilizing ECHO devices alone or in combination. Such gain adjustment maybe made through communications between ECHO devices and IBRs with thefeedback of measurements from receivers through the transmitting devicesand to the repeating devices. Such measurements may be made directly onsignal level or control signals such as pilot signals, control messages,imbedded pilot signals, spread spectrum CDMA signals or other pilottones or references signals within the signal or and associated out ofband channel. Additionally, the control communications may be made inone direction only or in both directions from IBR to ECHO device or ECHOdevice to IBR or may be made by an ECHO device transmitting to an IBRthat relays measurement commands or requests to the transmitting IBR viaa receiving IBR which in turn signals the transmitting ECHO device toadjust transmit power or gain or other associated receiving parameterssuch as receiving antenna selection, antenna switches, parameters in afeedback cancellation circuit associated with an interference cancellingrepeater or other RF parameters or signal processing parameters. Onesuch parameter may include the desired stability margin in aninterference cancelling repeater such that a specific signal-to-noiseratio or C/I is maintained at all times, or a minimum C/I is maintainedor a desired output transmission power is maintained or a particulargain is always maintained independent of the output power. Additionally,alarm conditions may be communicated in such a manner as requestedtransmit power or desired transmit power of an ECHO device being toohigh or isolation required for a desired gain setting being too low orinsufficient gain being possible and such parameters or performancemeasurements may be communicated either to IBRs or to a networkoperation center or other coordinating controller either co-located withIBRs, imbedded in IBRs or other ECHO devices or a remote serverconfiguring and optimizing the network in various embodiments.

FIG. 8A is a block diagram illustrating an exemplary single stream ECHORelay according to one embodiment of the invention. The operation ofthis embodiment is now described from receiving antenna structure 803-1through transmitting antenna structures 803-3 and 803-2. Antennastructure 803-1 may be a single antenna element or a plurality ofantenna elements utilizing a selection switch, or other phased array orbeam forming components. As an example depicted with reference to 803-1,antenna element 804 and 805 may be selected utilizing switch 801, acontrol Ctrl(1) such that one antenna element may be connected toreceive chain 810 at any given time. The antenna elements 804 and 805 inthe current embodiment are cross-polarized, one being a verticalpolarization and the other a horizontal polarization. However, in otherembodiments, there may be more than two antenna elements and the antennaelements may be directive antenna elements, patch antenna elements, orother types of antenna elements such as dipoles, collinear dipolearrays, directive array panels, Yagi elements and directional dishes orother types of single and two port antenna structures known in the art.Further, in yet other embodiments, the polarization of the individualantenna elements may be the same or vary, be orthogonal diagonally, orcircularly, while in yet further embodiments such elements may bedirective gain elements having differing angular orientations to providediversity. The description of antenna structure 803 x-y (where x and yrepresent any of the antennas in any of the figures) should beconsidered as any one or combination of the embodiments described hereinwithout the need to repeat those variations as described in additionalfigures in alternative embodiments of the ECHO devices.

Signal is received in ECHO device depicted in FIG. 8A as one embodimentat antenna structure 803-1 and coupled to receive chain 810. Receivechain 810 performs a band pass filtering function with filter 811. Thepurpose of band pass filter 811 is to provide for band selectivityallowing for operation in one or more channels of a relatively largeoverall bandwidth. Channel selectivity is performed using a heterodynestructure wherein low noise amplifier 815 provides amplification andmixer down converter 820 provides for frequency conversion utilizing alocal oscillator and intermediate frequency (IF) band pass filter (or“Channel Filter”) 825 performs channel selectivity. Filter 825 has abandwidth restricted to the operating channel bandwidth or slightlywider whereas band pass filter 811 has, in the current embodiment, awider bandwidth which allows for a flexibility of the operatingfrequency within an overall frequency band. IF band pass filter 825 maybe implemented with a ceramic filter, a surface acoustic wave (SAW)filter, a coupled-line filter, a lumped-element filter, or an activeanalog or digital filter that may be varied in bandwidth, or other suchtechniques as are known in the art.

Automatic gain control variable amplifier 830 is controlled utilizingAGC1 signal provided by Controller 840. Various AGC control algorithmsmay be employed. The AGC control provides for an adjustment in thereceived signal level and the overall gain of the repeater structureallowing for the control of the transmit power level from antennastructures 803-3 and 803-2. Directional coupler 836 provides for theinjection and extraction of signal to be received and transmitted byModem 835. The specific signals utilized by Modem 835 are describedlater in this specification. The operation of the modem is furthercontrolled and coupled to Controller 840. In this exemplary embodiment,the output of directional coupler 836 is coupled to delay element 837,which may also be a band pass filter in some embodiments or not presentin other embodiments. Divider 838 (which may also be called a“splitter”) provides for a splitting of the intermediate frequencysignal to two outputs. One output is provided to transmit chain withgain control block 850 while the other IF signal is provided to transmitchain and phase control block 851. Both blocks include a mixer upconverter 845 and 846 respectively for converting signal from IF signalin to an RF signal level and band pass filter 847 and 848 respectivelyfor filtering off mixer products which are not desired to betransmitted. The bandwidth of band pass filters 847 and 848 are the sameor similar in the current embodiment to band pass filter 811. TransmitAGC amplifiers 855 and 856 are controlled by controller 840 utilizingTx1Gain and Tx2Gain control signals. The outputs of the variable gainamplifiers 855 and 856 are coupled to power amplifiers 860 and 861respectively which are then coupled to transmit antenna structures 803-3and 803-2 respectively. Controller 840 controls the frequency of thevoltage controlled oscillator or numerically controlled oscillator invarious embodiments, 806, to produce a local oscillator signal which ispower divided by splitter/divider 807 and provided to mixer 820 as wellas up converters 845 and 846 and potentially other structures in variousembodiments. Additionally, control lines one through N_(c) provide forantenna selection control into antenna structures 803-1, 803-2 and 803-3as well as additional antenna structure selection controls inalternative embodiments having more than two antenna elements perantenna structure. Controller 840 within FIG. 8A acts to optimize theoperation of ECHO device depicted in the embodiments. For instance, thecontrol of the antenna selections to allow for a reduction in couplingbetween transmitted signals and the received signals of the ECHO devicemay be performed. Additionally, the adjustment of transmit gains,TxPhase as well as IF AGC1 gain allow for an optimization of transmitterto receiver isolation, and stability. For example, the control ofTxPhase to block 852 provides for phase shift of the local oscillatorsignal into up converter 846. The shifting of phase of the LO signalinto the up converter results in a phase shift of the IF signal inrelative to the RF signal out of block 851. Such an adjustment may actas a phase weighting capability for the signal transmitted out ofantenna structure 803-2. TxGain1 provides for gain settings of thetransmitted signal from antenna 802-2, while TxGain2 provides for thegain weighting of signal transmitted from 803-3. The adjustment of gainand phase of the two transmitted signals relative to each other allowsfor adjustment of the signal coupled back into receiver antennastructure 803-1. Additionally, the adjustment of IF gain, AGC1 byvariable gain amplifier 830 does not change the overall “isolation”between the transmit antenna and the receive antenna as the gain ischanged evenly between the two transmit chains. The optimization of theselection of the receive antenna, transmit antenna and transmit AGCs andtransmit phases relative to each other optimizes the transmitter toreceiver isolation allowing for maximum stability and gain in therepeater structure of the current embodiment and various embodiments ofthe ECHO device depicted in FIG. 8A.

The measurements of the relative stability of embodiments of FIG. 8A maybe provided by injecting a signal through the R Port of coupler 836 suchthat the signal injected is also transmitted out of antennas 803-3and/or 803-2 and coupled back to receive antenna structure 803-1, whichin turn is coupled through receive chain 810 to receive coupler port Fof coupler 836 and to receive port of modem 835. Because of the delaybetween the transmitted signal of the R port of 836 and its receptioninto the F port of 836 at the modem these signals, if chosenappropriately, may be uncorrelated such that using correlationprocessing allows for the discrimination of a transmitted signalrelative to the received “pilot reference” signal which was injected,transmitted, and re-received, and compared (or correlated) to theoriginally transmitted reference signal, allowing for an overallmeasurement of the isolation of the transmitted signal relative to thereceived signal including the gain provided by variable gain amplifiers830, 855 and 856. Adjustment of various parameters allows for anunderstanding of the overall isolation and gain stability of therepeater at any given time. When the signal is injected into coupler 836by Tx modem port of modem 835, the measured signal level from the F portinto the receive port of modem 835 must be less than or equal to thesignal level injected from the Tx port. Otherwise, the repeater isunstable and oscillate. In fact, the ratio of the transmitted pilotsignal to the receive signal from modem 835 additionally defines theoverall carrier to interference ratio and signal to noise ratio that therepeater supports. Additionally this ratio of transmit power divided byreceived power of the reference pilot signals provides for a stabilitymargin of the repeater. In general, such a stability margin is adjustedto be at least—15 dB and ideally—20 dB or more. Generally the amount ofgain from the output of antenna structure 803 through the input of theantenna structures 803-3 and 803-2 must be less than the overallisolation minus the stability margin and thus the adjustment of thevarious variable gain amplifiers may be computationally computed usingMMSE approaches of the transmitted and received reference signal oralternatively utilizing an adaptive approach such as the steepest decentalgorithm to achieve maximum isolation utilizing Tx1Gain, Tx2Gain andTxPhase while AGC1 would be adjusted based upon a target isolationmargin based upon the isolation margin measured as a ratio of TX powerto RX power of modem 835 utilizing pilot signal measurements. Note thatthe power levels may be frequency selective and therefore an approachmonitoring the frequency specific isolation margin may be appropriate inspecific embodiments. Such a pilot signal may further includeinformation that, since it is being transmitted as pilot tone, may alsocarry this information such that the information may be communicated totarget devices such as receiving IBRs. Further other modulated pilotreference signals may communicate information to the ECHO device fromtransmitting IBRs such that the status and control information may becommunicated and received to modem 835 and ultimately to controller 840allowing for the optimization of transmit gain isolation margins and theadjustment of various parameters as described herein.

In another embodiment of an ECHO device depicted in FIG. 8A, thetransmit antenna structures 803-2 and 803-3 include a singletransmitting antenna each, one having a vertical polarization and theother having a horizontal polarization, whereas receive antenna 803-1has a single polarization, which, in one embodiment, is a verticalpolarization. The transmit gains and/or the transmit phase of transmitchains 850 and 851 may be adjusted so as to provide maximum isolationbetween the transmitters and the receiver antennas. If no scattering onthe structure of ECHO device of the current embodiment is encounteredthen there is only coupling predominantly between the vertical transmitantenna and the vertical receive antenna. Thus, making the transmit gainof the vertical antenna element 803-2 such that all the transmit poweris transmitted from horizontal transmit antenna element 803-3 may bepreferable. However, in practice some cross-polarization between thetransmit antennas and the receive antenna elements occurs and thereforehorizontal transmit antenna 803-3 in the current embodiment may providefor the maximum transmit power used to transmit to the target devicewhich may be another ECHO device or an IBR while transmit antennaelement having vertical polarization 803-2 may be used to null thecross-polarization leakage signal from horizontal transmit 803-3 backinto vertical receive antenna element 803-1. The phase adjustment byphase shifter 852 and a gain adjustment by Tx1Gain control via variablegain amplifier 856 allows for fine grain adjustment of the cancellationsignal coupled to the receiver antenna. However, such a structure is notfrequency selective and may only consider a single phase shift, not anequalization approach. Other embodiments within this disclosure discussequalization structures, which allow for frequency selectivecancellation and feedback. In further embodiments of FIG. 8A the antennadevices may be fixed and mounted high gain antenna structures, whichduring installation may be articulated and aligned, then permanentlymounted with mechanical adjustments in azimuth and elevation alignmentsettings, so as to provide appropriate signal reception and transmissionto target devices. Additionally adjustments are made to providereasonable isolation between the transmitter and the receiver. Part ofthis adjustment may include the operation of Controller 840 so as toperform adaptive gain and phase adjustments to perform isolationenhancement such that a closed-loop system may be considered duringinstallation. Once again, this closed-loop process may be facilitatedutilizing Modem 835 and a pilot reference signal used for measuring theisolation between the transmit to the receive. In alternativeembodiments, an electromechanical adjustment may be made to fine tunethe alignment of the antenna structures to achieve the designed receivesignal level, target receiver alignment, and desired transmit to receiveisolation. Such adjustments are during initial installation, orperiodically during operation by the controller 840 using appropriatecontrol of electromechanical structures.

An additional function for Modem 835 may be utilized in embodimentswhere some of or each of every packet or signal received into therepeater are qualified before enabling the transmitter. Such conditionsmay be required to meet certain regulatory operation of repeaters insome embodiments in unlicensed frequency bands such as Part 15.247operation. Operation of such a qualification mechanism might be enabledutilizing coupler 835 and specific embodiments in which a signal with aburied pilot reference tone and information signal from a transmittingIBR is detected by Modem 835 and upon detection qualifying the signal asan appropriately received signal which is allowed per regulatoryrequirements to be transmitted preventing the repeating of arbitrarysignals which may not be qualified for repeating by the ECHO devices (orrepeaters). Upon the detection of the qualifying tone embedded withinthe signal to be repeated or relayed, Modem 835 alerts Controller 840which then makes adjustments enabling the repeater to perform therepeating function. This repeating function and enablement may have atime out associated with it such that the qualification of a specificsignal as being permissible to transmit and repeat may require the pilottone or a “signature tone” to be present for a specific period of timeprior to enabling the transmitter and require the transmitter to turnoff in the ECHO device if such a tone disappears or is not received fora specific period of time.

FIG. 8B is a block diagram illustrating an exemplary single stream ECHORelay including a Frequency Translating Feedback Canceller according toone embodiment of the invention.

Referring now to FIG. 8B, an alternative embodiment of an ECHO deviceutilizing a “Frequency Translating Feedback Canceller”, is depicted.Antenna structures 803B-1, 803B-2 and 803B-3 are equivalent to thosepreviously described as 803-1, 803-2 and 803-3 in various embodimentsincluding alternative antenna structures. Bandpass Filter 811B isapplied to the output of the selected of the signal received by 803B-1.Low noise amplifier 815B provides amplification to the signal, whichthen is coupled to a summer 875B. Summer 875B provides the combinationof the received signal with the output of the frequency translatingfeedback canceller 807B from its output port RFOut-2. The signalproduced by RFOut-2 of 870B is provided so as to null repeatedtransmitter leakage from Antenna 803B-2 and 803B-3 into antenna 803B-1providing for additional isolation and stability margin allowing foroperation at higher gain levels. Downconverter 820B provides for aconversion of the summation of the received signal and the cancellationsignal from the frequency translating feedback canceller such that anintermediate frequency signal is produced and filtered utilizing ChannelFilter 825B. Variable Gain Amplifier 830B provides for the overall gainadjustment for the repeater and typically is used in conjunction withController 840B making adjustments in transmit isolation margin orstability margin utilizing AGC1 control signal. The operation of theModem 835B is similar in specific embodiments to that of 840 of FIG. 8Aincluding the use of control reference and information signals forcommunicating with other devices and receiving communications from otherdevices as well as pilot signals for measuring and adapting the variouscontrol parameters associated with enhancing the isolation margin of therepeater and making gain adjustments to 830B and other gain settings.The output of Coupler 836B, including injected and coupled pilot signalsin some embodiments, passes through a Delay Element 837B and Splitter838B. Port 1 of the splitter goes to the “Transmit Chain with GainControl” 850 which up converts the signal as described previouslyassociated with FIG. 8A, which then transmits the signal utilizingantenna structure 803B-3. The second port of Splitter 838B is coupled tothe IF input of frequency translating feedback canceller 870B. “I” offrequency translating feedback canceller 807B indicates the number ofoutput ports associated with the canceller. The frequency translatingfeedback canceller 807B receives a local oscillator signal as well as acancellation control, the cancellation control coming from Controller840B, the LO coming from Splitter 807 for use in up converting the IFinput signal to the plurality of RF Output Signals RFOut-1 and RFOut-2(in the current embodiment). It is envisioned that in specificembodiments depicted herein the signal transmitted from 803B-3 may bedirected toward the target device. Such a signal may include a verticalor horizontal polarization or both in a directed gain element positionedin azimuth and elevation so as to transmit to a target device. TransmitAntenna 803B-2 may be utilized to perform cancellation into ReceiveAntenna 803B-1. RFOut-1 is coupled to PA 860 to achieve the transmitcancellation function. Furthermore, RFOut-2 of frequency translatingfeedback canceller also provides a direct cancellation signal into thereceiver chain of the ECHO device. Controller 840B utilizing cancellercontrol signals provides adjustments to structure 870B so as to enhancethe overall isolation margin and maximize the desired gain of the ECHOrepeater of the current embodiment. In an alternative embodiment theoutput of frequency translating feedback canceller of RFOut-1 andAntenna 803B-2 may further be used to communicate with the target IBRdevice allowing for adaptation of polarization or beam forming or othertransmit diversity mechanisms or pattern mechanisms such as phasedarrays or beamformers in conjunction with Transmit Antenna 803B-3allowing for higher performance reception at the target receivingdevice.

Furthermore Modem 835B may be in communication with the target receivingdevice which may relay control signals to transmitting IBR or ECHOdevice, which may perform a similar beam forming or polarizationadaptation allowing for an adjustment of the received polarization orgain or multipath at Receive Antenna 803B-1 to allow for an enhancedisolation of the ECHO device embodiments depicted in FIG. 8B.

In alternative embodiments, more than one transmitter may be coupled tofrequency translating feedback canceller 870B where “I” may be equal to3 or more. In such an embodiment the additional transmitters may be usedto perform frequency selective nulling or spatial beam forming inconjunction with RFOut-1 and Antenna 803B-2 to allow for furthertransmitter to receiver isolation for the ECHO device or enhancedperformance of the transmit signal to the target device.

FIG. 8C is a block diagram illustrating an exemplary FrequencyTranslating Feedback Canceller according to one embodiment of theinvention. Various embodiments are enabled by the structure of FIG. 8Cincluding an arbitrary number of RF out signals from 1 to “I”. IF inputsignal 802C is received into up converter 805C, which utilizes LO 803Cto provide for an upconverted input signal into band pass filter 811C.The band pass filter 811C is of equivalent bandwidth in some embodimentsto that of 811B and is intended to select the band of operation, not thespecific channel of operation in specific embodiments. Splitter 812Cprovides for a split input and filtered RF signal to the plurality oftransversal RF equalizers comprising 820C-1 through 820C-I. CancellerControl 804C is coupled to the plurality of RF Equalizers 820C-1 through820C-I. RF Feedback Canceller 810C includes all the components of thefrequency translating feedback canceller with the exception of theup-conversion functionality provided by 805C in specific embodiments.Individual RF Equalizer 820C-1 is equivalent in function to 820C-2through 820C-I. The RF signal from Splitter 812C is provided to theinput of 820C-1 which is coupled to Delay Element 821C and Gain andPhase Adjuster 825C. Gain and Phase Adjuster 825C includes a GainAdjustment Element 826C which may be a variable gain amplifier or avariable attenuator in another embodiment, or alternatively, may inconjunction with Phase Shifter 827C be a vector modulator or complexmultiplier circuit in alternative embodiments. The output of Gain andPhase Adjuster 825C is provided to Summer 830C. 830C receives aplurality of inputs from a plurality of gain and phase adjusters. Eachgain and phase adjuster is coupled to a different delay of the input RFsignal to 820C-1. The output of Delay Element 821C is provided to aplurality of additional delay elements, each of which is coupled to aGain and Phase Shift Element 825C so to provide gain and phase weightedand delayed inputs from Ot_(o) (no delay), Δt_(1,i) (821C) throughΔt_(J(i)i) (823C). The output of the combination of the Gain and PhaseAdjusters 825C of 0 through J(i) are summed by 830C and provided asRFOut-1 Signal 806C. Likewise similar functionality is provided forRFOut-2 through RFOut-I 808C.

FIG. 8D is a block diagram illustrating an alternative exemplaryFrequency Translating Feedback Canceller according to one embodiment ofthe invention.

In an alternative embodiment of frequency translating feedback cancellerthe IF Input Signal 802D is first split utilizing Splitter 812D andprovided to Frequency Translating Equalizer 820D-1 through 802D-I,wherein the Gain and Phase Weight Elements 825D additionally includeMixer 828D, collectively to perform gain, phase, up-conversion andfiltering functionality. One benefit of including phase shifterincorporated with gain and up-conversion is that the phase adjustmentmay be applied to the local oscillator signal from Splitter 810Dallowing for a very consistent phase shifting across frequency, so as toapply a phase shifted LO to Up-converter 828D resulting in a phaseshifted up-converted signal where there is no frequency selectivity orfrequency dependence associated with the phase shift, but rather a veryflat and broadband phase shift functionality, which may be applied andfurther which is advantageous in some embodiments. Gain Adjustment 826Dis then applied in band pass filter 829D collectively comprisingUp-converting Gain and Phase Adjuster 825D. Furthermore, the phase andgain and up-conversion functionality may be applied by a complexmultiplier or vector modulator circuit in alternative embodiments. Aswith the previous embodiments, the output of delayed copies of the inputsignal through Delay Elements 821D, 822D, 823D, and so forth, are summedto provide a frequency equalized RF output signal. RFOut-1 throughRFOut-I, respectively 806D to 808D, are then provided as the output tothe frequency translating feedback canceller. As previously described,one or more of the RF out signals may be used as transmit signalscoupled to power amplifiers and transmit antennas whereas one or more RFout signals may be used as direct feedback signals and summed withreceive signals directly utilizing a summer.

FIG. 8E is a block diagram illustrating an exemplary dual stream ECHORelay including Frequency Translating Feedback Cancellers according toone embodiment of the invention. FIG. 8E depicts an embodiment of anECHO device wherein two signals may simultaneously be repeated orrelayed. Receive Antennas 803E-1 and 803E-2 may include a singledirective antenna structure with cross polarization output ports or maya plurality of elements as previously described. It is envisioned thatsome embodiments of these antennas may have mechanical orelectromechanical articulation so as to maximize the received signallevel from a transmitting IBR or ECHO device while minimizing couplingto the Transmit Antennas 803E-4 and 803E-3. The input signals fromAntennas 803E1 and 803E2 are passed to Receive Chains 810E-1 and 810E-2which have Gain Control Signals AGC-1 and AGC-2 respectively and coupledto Controller 840E. The outputs of the receivers are respectivelycoupled to Coupler Devices 836E-1 and 836E-2 each of which includescoupler ports coupled to Modem 835E in the current embodiment. Modemreceive port (MRx-1) and Modem transmit port (MTx-1) are coupled tocoupler 836E-1 while MRx-2 and MTx-2 are coupled to coupler 836E-2associated with Receive Signal from antenna structure 803E-2. Thefunctionality of Modem 835E is such that the same or different pilotsignals may be transmitted through MTx-1 and MTx-2. In one embodiment,different signals are transmitted from MTx-1 and MTx-2, allowing formore discrimination of the coupling effects between Receive Chain 810E-1and 810E-2 and Transmitter Antenna Elements 803E-4 and 803E-3. Next theoutput of Couplers 836E-1, 837E-2 are respectively coupled to DelayElements 837E-1 and 837E-2 which in some embodiments may additionallyact as filters. Such filters may be implemented as SAW devices providingfor delay and filtering functionality. The output of Delay Elements837E-1, 2 are coupled to Frequency Translating Feedback Cancellers870E-1, 2 respectively and contain functionality as previously describedin embodiments associated with FIG. 8C and FIG. 8D. The outputs of870E-1, 2 are then coupled to Combiners 813E-1 and 813E-2, whichrespectively combines Frequency Translating Feedback Canceller outputs,which are respectively coupled to PAs 960E-1, 2 and Transmit Antennas803E-4, 3 respectively. These antenna elements may have orthogonalpolarizations in specific embodiments on both the receive side and onthe transmit side so as to cause 803E-1 to have an orthogonalpolarization to 803E-2 and 803E-4 to have an orthogonal polarization to803E-3 allowing for a cross-polarization of similar signals. Forinstance, the signal received on 803E-1 may mainly be transmitted out ofRFOut-2 of 870E-1 and Antenna 803E-3 while RFOut-1 port may be used togenerate a cancellation signal to further isolate the coupling from803E-3 antenna to Receive Antenna 803E-1 whereas the opposite is truewith the Feedback Canceller 870E-2. The Transmit Antenna 803E-3 providesthe cancellation signal for coupling to Receive Antenna 803E-2 whereasRFOut-1 of 870E-2 is utilized in some embodiments for the primarytransmit signal out of 803E-4. As a result, each frequency translatingfeedback canceller is responsible for a transmit signal out of one RFOutport and a cancellation signal out of the other RFOut port and couplesthe transmit signal to the opposite polarization from its associatedreceive antenna and provides a cancellation signal to the RFOut portwith a similarly associated transmit antenna polarization to itsrespective receive antenna polarization.

In alternative embodiments associated with the ECHO device of FIG. 8E,additional transmit output ports may be configured so as to causefrequency translating feedback canceller 870E-1 or 870E-2 to have morethan two RF output ports allowing for a plurality of transmit antennasbeyond the two transmit antennas 803E-3 and 4, depicted in FIG. 8E,allowing for additional spatial beam forming techniques. Such beamforming techniques provide for an enhanced transmit capability to targetIBRs or ECHO devices, as well as for further isolation between thetransmit and receive antennas, allowing for additional gain performanceof the ECHO device with increased stability margin. In such a case,controller 840E provides additional control information to eachfrequency translating feedback canceller, so as to optimize theirperformance. In yet other embodiments, more than two receive chains andreceive antennas may be utilized with additional frequency translatingfeedback cancellers, allowing for additional receive signals for thesupport of more than two streams based on polarization or based uponspatial multiplexing or separation.

In some embodiments with two receive chains and two receive antennas,polarization isolation between the two receive chains and antennas maybe used or alternatively spatial separation may be utilized inconjunction with transmit beam forming from the transmitting IBRs orECHO devices. In such an embodiment, feedback from controller 840E viamodem 835E to target IBR coupled to transmitting IBR or transmittingECHO device may be utilized to optimize the transmit beam formingparameters. Additionally, in alternative embodiments utilizing aplurality of receive chains beyond the two depicted in FIG. 8E, areceived beam forming functionality may be provided by combining thereceive signals from each receive chain with appropriate waiting,utilizing the frequency translating feedback cancellers into combiners813E-1, 813E-2 and beyond. Such receive beam forming capability may beutilized in embodiments with two or more receive antennas and receivechains utilized. The performance of this beam forming capability isfurther enhanced with additional receive chains employed in variousembodiments. In yet further embodiments, the combination of feedbackfrom controller 840E to the transmitting source (IBR or another ECHOdevice) enables an optimization of transmit beam forming weights. Suchtechniques may be employed in combination with receive beam formingprocessing allowing for further optimizations to be performed. Furtherinformation received by the modem from the receiving target of thetransmissions from 803E-4 and 803E-3 may be utilized as a metric for theoptimization of transmit beam forming from the current ECHO device forspecific embodiments associated with FIG. 8E as well.

Additionally, in the case of an ECHO device receiving MIMO signalshaving multiple streams, the adaptation of transmit antenna patternsfrom a transmitting device to embodiments of ECHO devices may providefor a separation of one stream being predominantly received at 803E-1and another stream being predominantly received at antenna structure803E-2. Such a process may additionally be achieved utilizing a receivebeam forming function performed in combination with or separate from thetransmitting IBR or source ECHO device. Having a receive antennastructure and associated receive chain with predominantly one stream,relative to another receive chain, provides for specific performanceadvantages when operating in a multiple stream environment so as toprevent a “co-stream” AGC capture resulting in the suppression of acommon non-dominant information stream by an automatic gain controlalgorithm. Such common stream AGC capture provides a reduction in therank of the effective end-to-end channel propagation matrix, therebyreducing the number of supported streams.

FIG. 8F is a block diagram illustrating an exemplary dual stream ECHORelay, including Frequency Translating Feedback Cancellers, thatutilizes internal feedback according to one embodiment of the invention.Referring now to FIG. 8F, the functionality of embodiments associatedwith FIG. 8E are further depicted in FIG. 8F with the additionalfunctionality of feedback canceller 870E-1 and 2, having an additionaloutput port coupled to each of the receive combiners 875F1 and 875F2,providing for feedback cancellation directly into the receiversassociated with receive antennas 803F-1 and 803F-2. Such a structureallows for direct frequency selective cancellation from each of thefrequency translating feedback cancellers (with “I”=4) into each of thereceive channels, as well as providing for transmit signal and/orcancellation signal transmission from each of the transmit antennas803F-4 and 803F-3. Providing for direct feedback cancellation to bothreceivers from each of the feedback cancellers allows for furtherdegrees of freedom for the use of the transmit antennas to be used fortransmit spatial beam forming rather than feedback cancellation inspecific embodiments. Further modem 835F provides, in specificembodiments, injected pilot signals into MTx-1 and MTx-2 of couplers836F-1, 2, respectively, to allow for the optimization of transmit gain,receive signal, and transmitter to receive isolation, as well asstability margin parameters. MRx-1, 2 into modem 835F further allows forreceiving of communications control information and pilot informationfrom the target receiver transmitting to the ECHO device of embodimentsdepicted in FIG. 8F, allowing for the optimization of receiveparameters, as well as transmit parameters, based upon receiving of theinjected pilot in communication signals from the modem. In yet otherembodiments, more than two receive antennas, receive chains andfrequency translating feedback cancellers may be utilized with two ormore transmit antenna elements and associated transmit chains. Thenumber of receive chains and feedback cancellers need not be equal tothe number of RFOut ports. In some embodiments only two transmit RFoutput ports are present while more than two receive chains may bepresent in each ECHO device. In specific embodiments, each receive chainmay receive a subset of the output of the frequency translating feedbackcancellers whereas in other embodiments each transmitter receivesoutputs from each and every frequency translating feedback canceller. Itis important to recall that in addition to cancellation, each frequencytranslating feedback canceller may be optimized to additionally providefor the transmission of the repeated or relayed signals so as tooptimize their reception at the intended receiving IBR or target ECHOdevices.

Embodiments of the forgoing ECHO relays may be used in pairs or sets soas to enable FDD, ZDD, or TDD configurations of point-to-point andpoint-to-multipoint wireless networks. As an example, two unidirectionalECHO relays may be independently operated so as to enable a respectivedirection of a TDD link. The control of such ECHO relays may be operatedin a number or approaches including utilizing the composite controlchannel to perform detection of transmissions intended for repeating orrelaying signal in one direction utilizing a first of the two ECHOdevices, which may occur in one set of TDD directions and timings.Additional control may be provided by the ECHO controller so as to allowfor the synchronization of the TDD links so as to only allow forrepeating at pre-determined timings, which correspond to one of theplurality of TDD communications timings. The second of the two ECHOdevices would be configured in a similar way so as to repeat the timingand detections enabling communications in the opposite TDD linkdirections. In such configurations, the two or more ECHO devices may beco-located or each may be positioned at different locations.

In FDD configurations two or more ECHO devices may be configured so asto each turn their band and/or channel selection so as to repeat orrelay differing frequency channels. Further the arrangement ofdirectional antennas (as is the case with TDD configurations) may bealigned so as to support optimized signal transmission and reception tothe intended network nodes (IBRs or other ECHO device), which are theirrespective intended signals to relay or repeat.

In ZDD operation, the individual ECHO devices maybe advantageouslypositioned by respectively aligning direction antennas in separatelocations, providing for additional transmitter and receiver isolationbetween the two ECHO devices despite operating at the same frequencychannels. In other embodiments, a single ECHO device of FIG. 8F, forexample, may be utilized such that a subset or receive and transmitantennas may each be arranged to support ZDD relaying or repeating inone or both specific physical directions and feedback cancellation maybe utilized so as to provide stability between both the respective Rxand Tx subsets of antennas, but additionally between the oppositelyarranged sets or receivers and transmitters. Such an arrangement allowsfor the operation of a bi-directional ZDD ECHO relay device in a singleunit. The description of additional configurations follows, each ofwhich may be embodied as explained as multiple ECHO devices, orintegrated as a single device in various embodiments.

FIG. 8G depicts a block diagram illustrating an exemplary FDD/ZDDconfiguration of two dual stream ECHO Relays according to embodiments ofthe invention. The embodiments of 850G-1 and 850G-2 may be any one ofthe disclosed embodiments and in any variation or combination. Thedashed lines 805H-1, associated with ECHO-A, and 805H-2, associated withECHO-B, depict the direction of the processing of the signals from thereceive antennas (803G-3 and 803G-4 of ECHO-A and 803G-5 and 803G-6 ofECHO-B) to respective transmit antennas (803G-1 and 803G-2 of ECHO-A and803G-7 and 803G-8 of ECHO-B). In the case of FDD operation, ECHO-A tunesto one frequency channel, and ECHO-B tunes to another frequency channel.The two FDD channels may be in the same or different frequency bands. Insuch an embodiment, control information may be shared between therespective ECHO controllers of the various embodiments of 8050G-1 and8050G-2 using control lines 820G-1. Alternatively, a single controllershared between the two devices may provide the control described herein.In embodiments where frequency translating feedback cancellers areutilized, cross device cancelation signals may be shared using 820G-2and 820G-3 RF Output and RF Input connections. Such cancelation signalsmay be received into the respective ECHO device and injected into thereceivers or the transmitters as described herein, including thoseembodiments described with reference to FIG. 8F. Such cancelation may behighly beneficial when the separation of operation of the frequencychannels for frequency duplexing is small relative to the filteringcapability of the individual ECHO devices. When configured for ZDDoperation, the embodiments of FIG. 8G include tuning the individual ECHOdevices (850G-1 and 850G-2) to the same or overlapping channels ofoperation.

FIG. 8H depicts a block diagram illustrating an exemplary TDDconfiguration of a dual stream ECHO Relay according to embodiments ofthe invention. In various embodiments of FIG. 8H the ECHO deviceoperates in a time division duplexed mode, wherein during one timeperiod signals from antenna 803H-1 and 803H-2 are coupled to the receiveports of ECHO device 850H-1, respectively by switches 815H-1,-2 and815H5-5,-6. The ECHO device 850H-1 then performs processing, aspreviously described herein, and couples the transmitter signals toantennas 803H-3 and 803H-4 respectively by switches 815-3,-4 and815H-7,-8. Dashed arrows 805H-1 and 805H-2 indicate the signal flow ofthe foregoing description. During the opposite time periods, whencommunications are in the opposite direction to that of the oppositetime duplexing periods, the controller of ECHO device 850H-1 changes thecontrol (SW Control) causing the switches to change their selection ofcoupled ports. In such arrangements, the signal flow does not proceed asdepicted in dashed lines 805H-1 and 805H-2, but in the oppositedirection, from antenna structures 803H-3 and 803H-4 respectively toantenna structures 803H-1 and 803H-2. The signals from antennastructures 803H-3,-4 are respectively coupled to switches 815H-4,-8,which couple the respective signals to the receive ports of 850H-1 viaswitches 815H-2 and 815H-6. The transmit ports of 850H-1 provide theirrespective output signals to switches 815-3,-7 respectively to antennastructures 803-1,-2 via switches 815H-1 and 815H-5. In some embodimentsof 850H-1, the controller of the ECHO device, where beam forming and orfrequency translating feedback cancelation is utilized, causes the valueof the various control to be adapted and applied independently betweenthe two time duplexed time periods.

FIG. 8I is an exemplary block diagram of an ECHO Modem including anEmbedded Link Processor (ELP). The ELP 8I-500 functions as describedabove with reference to the ELP 500 of FIG. 5A, FIG. 5B, and FIG. 5C.Embodiments of ELP 8I-500 provide for the functionality of ELP 500, withno pass-through data summation of a Transmit Symbol Stream input to theELP. The RRC block 8I-360 and RLP block 8I-356 generally providefunctionality similar to the RRC 360A and RLP 356A of FIG. 3A. ECHO MAC81-312 provides MAC control functions and MAC Protocol Data Units(MPDUs) to ELP 8I-500. Transmit Symbol Streams including EmbeddedControl Channels DTx-1 and DTx-2 are digitally sampled informationhaving 12 bits real and 12 bits imaginary data, in one embodiment.Likewise, receive symbol streams including Embedded Control Channels(RTx-1 and RTx-2) are digitally sampled information having 12 bits realand 12 bits imaginary data, in one embodiment. ECHO Channel Converter8I-328 provides digital to analog conversion and associated filtering tointerface with Modem RF 8I-332. Likewise, analog receive signals fromModem RF 8I-332 are converted to digital samples resulting in receivesymbol streams with Embedded Control Channels by ECHO Channel Converter8I-328.

FIG. 9A is a flow diagram for an ECHO Relay at the controller, accordingto one embodiment of the invention. FIG. 9A further provides adescription of embodiments of the ECHO repeater and a flowchartdepicting specific embodiments of the control and operation of a statemachine associated with the controller modem and functional elements ofembodiments of the ECHO repeater.

In Step 910A, the ECHO device initializes upon power-up. Initializationmay include self-tests, configuration, reading of stored parameters fromnon-volatile memory, the application of those parameters, specificmeasurements associated with isolation, calibration associated withadjustments in gain and phase of various components and the like.

In Step 915A, the ECHO device is configured based upon storedprovisioning information associated with items such as the signaturesignal or other parameters associated with pilot signals associated withqualified source signals to which the repeater is to search, and toallow for use as a pilot signal, or in the communication with otherdevices. For instance, an example of stored parameters, in specificembodiments, would include the desired gain of the repeater or storedequalizer settings and the like.

Additionally, parameters associated with the “composite control channel”configuration, a broadcast control channel configuration, controlsub-channels for receive and transmit signaling for specific ECHOdevices are also determined. The composite control channel, in someembodiments, may be as simple as a spread spectrum pilot signaltransmitted from the source transmitter of the signal to be repeated bythe instant ECHO device, or it may be as complex as the summation of aseries of signals.

One embodiment of a composite control channel may be a direct sequencespread spectrum signal with a chip rate of 25 nanoseconds for anoccupied bandwidth of approximately 40 MHz. In such an embodiment, therepeater bandwidth may also be 40 MHz (though not required to be thesame), which would be equivalent to the intermediate frequency band passfilter bandwidth as described in various embodiments for the IF channelselection filters. Such a chip rate would additionally allow for thediscrimination of time delays from the transmitter of the instant ECHOdevice to the receiver of the same ECHO device. Such temporaldiscrimination, in steps of 25 nanoseconds, are achieved as thecorrelation peaks resulting from a correlation process between a storedcopy of the reference pilot signal injected into the repeater by themodem, and a delayed copy of the injected pilot reference signal whichhas been received as “leakage” from the instant ECHO transmitter intoone or more of it's own receivers. Following the injection of the pilotreference signal into the instant ECHO device, the reference pilotsignal is transmitted along with the repeated source signal. Thetransmitted signal from the instant ECHO device, including the injectedpilot reference signal, is received as leakage signal into the receiverin the same ECHO device. As mentioned, the coupled and “leaked” pilotreference signal is detected, in one embodiment, by performing acorrelation between a stored copy of the transmitted pilot referencesignal with the received leaked pilot reference signal in the modem835F. For instance, Modem 835F performs a correlation of stored copiesof the transmitted waveforms into MTx-1 and MTx-2 wherein the delay D1and D2 would have a delay in excess of a multiple of 25 nanoseconds, orin general, the current signal chip rate. Alternatively the delaysrequired to discriminate the correlation peaks of the transmitter fromthe receiver pilot reference signals may be provided inherently withincomponents such as the IF band pass filters or the like.

The foregoing processing allows for the transmitted and receivedwaveforms to be discriminated versus time delay using such correlationprocessing. Such processing prevents the un-delayed injected signals(MTx-1, 2, . . . Q) from being confused with the delayed and coupledpilot reference signal transmitted from Antennas 803F-4 and 803F-3 andreceived by receive Antennas 803F-1 and 803F-2. Therefore, in thisembodiment, the chip rate must be high enough so as to allow thistemporal discrimination of the transmitted signals pilot referencesignals relative to the coupled and received leaked pilot referencesignals. Note that in alternative embodiments, the correlation need notbe performed based upon a modem (such as 835F) injecting the pilotreference signal, but based upon a pre-existing pilot reference signalpreviously added to the source signal to be repeated. Such a signal maybe a pilot reference signal as described herein, but injected by asource IBR or ECHO device. The foregoing correlation process remainseffective so long as the stored reference of the pilot reference signalis contained within the received source signal; thereby allowing thetransmitted and repeated signal in view of the delay of the ECHO deviceto continue to provide temporal discrimination of the leakage signalrelative to the source signal as described.

In additional to being used for transmitter to receiver interferencemanagement, the pilot reference signal includes a portion of or theentire composite control channel. The chip rate of the composite controlchannel must be high enough so as to allow the signal informationcarried to be spread over the 40 MHz or an appropriate bandwidth, thebandwidth being the inverse of the chip rate, and as a result providingprocessing gain. Such processing gain is important for a number ofreasons, including that it allows for the composite control channel tobe “buried” within the source signal to be repeated. The compositecontrol channel, in some embodiments, may act as a noise source to thequality of the repeated signal, resulting a limitation of the signal tonoise ratio (SNR) of the desired source signal to be repeated. Thereforeinjecting the pilot reference signal or other components of thecomposite control channel at a lower signal level relative to thereceived source signal allows for minimizing the impact to the repeatedsignal SNR.

Such processing gain is approximately equal to 10*log₁₀(BW/BR), whereinBW is the bandwidth of the composite control channel and BR is the bitrate of the information carried within that channel. For instance, abandwidth of 40 MHz divided by an information bit rate of 1000 bits persecond would result in 46 dB of processing gain. As a result the powerlevel of the signal transmitted from Modem 835F in specific embodimentsmay be equal to the received signal strength indicator (RSSI) from thecoupler minus 35 dB, for example, such that the received informationsignal of the injected pilot signal would have a signal-to-noise ratioof 46 dB−35 dB=11 dB signal-to-noise ratio (SNR). Thus, the injectedsignal would be “buried” by 35 dB relative to the source signal to berepeated. Such an SNR (11 dB) would be more than sufficient typicallyfor the demodulation of a BPSK signal in one example. In alternativeembodiments, different ratios of the RSSI to the transmitted injectedspread spectrum signal or composite control channel into Coupler 836F-1and 836F-2 may be used so as to optimize particular desired informationrates and performance. For instance, a desired information bit rate of100 bits per second would provide for an additional 10 dB of processinggain, thereby allowing for the signal to be injected at least 10 dBlower than in the previous example.

The structure of a composite control channel in one embodiment is aspread spectrum signal with a chip rate of 25 nanoseconds, as discussed,and additionally include an orthogonal code such as a Walsh function,which allows for each injected signal to be orthogonal with all otherinjected signals providing for less interference between differentinjected signals comprising a composite control channel. Each injectedsignal may be from a different ECHO device, IBR, or ECHO MODEM channel(MTx-i). As a result, signals in each control channel collectively sumtogether in an orthogonal mode, and the composite control channel, inone embodiment, is made of injected and synchronized signals frommultiple sources. Each orthogonal code may be assigned to an IBR or anECHO device or ECHO device IF modem coupler (such as 836-1 and 836-2 forexample). Such an arrangement allows for specific sub-channels to beutilized to listen to transmissions from specific IBRs or ECHO devicesor to transmit from a specific IBR or ECHO device. Alternatively theorthogonal codes may be assigned according to the receiving devicerather than the transmitting device.

In one embodiment, the orthogonal code is synchronized to specifictimings of the PN code (potentially already embedded with the sourcesignal), so that all orthogonal codes for all such sub-channels areappropriately aligned in time so as to maintain orthogonally in apre-determined configuration of the timing retrieved from non-volatilememory. The PN code, as is known in the industry, may be a maximallength M code, a Golay code, a gold code or any one of codes known andused in the art. Further the orthogonal codes may be Walsh codes, WalshHadamard codes, CAZAC codes, Zadoff Chu codes, or any one of a number oforthogonal codes that are known in the art. The modulation used on thechannel may be BPSK, QPSK, QAM, FSK, AM, OFDM or any number of knownmodulations. Furthermore, a DSSS or CDMA modulation such as that used in802.11, IS-95, CDMA2000 or WCDMA/HSPA may be employed.

Upon provisioning, the specific assignment of orthogonal codes, in oneembodiment, to specific target transmitters and target receivers of theECHO device are stored in non-volatile memory. The specific PN sequenceare stored to allow the ECHO device to first search for the PN sequencewithin the source signal and then to search for the specific sourcetransmitter to which it is assigned to be repeating or relaying as wellas the signals for each stream from a specific IBR. Differentembodiments may have a different orthogonal code assigned to each sourcestream to be repeated or relayed.

Such a composite control channel signal may carry information in theform of a BPSK signal and may carry pilot channels or symbols thatprovide for phase reference. In one embodiment, a pilot channel, whichmay have the Walsh 0 code (all ones or all zeros), is provided, whereasother sub-channels may have other Walsh codes configured for them.

As the configuration process of FIG. 9A continues in Step 915A, abroadcast control channel or sub-channel with a specific assigned Walshcode is configured which includes, in some embodiments, informationassociated with the current performance of the network or updatedparameters or potentially software updates or the like. In someexemplary embodiments, a particular control channel may be assigned toconvey updated software for an instant ECHO device while continuingnormal operation of such device as a repeater or relay. Such softwareupdate control channel, or another designated control channel, may alsoconvey messages causing such ECHO device to stop repeating designatedsource signals temporarily in order to change over to such updatedsoftware. For example, such a change over may be scheduled at a timewhen data networking traffic amongst the IBRs is minimal such as in themiddle of the night.

The control sub-channels for receive and transmit signals for a specificECHO device may also be communicated over the broadcast control channelallowing the specific Walsh codes or orthogonal codes in variousembodiments to be dynamically assigned to each device within the networkbased upon the serial number or other unique identifiers of each ECHOdevice within the network. Such an approach may be similar to DHCP forIP address assignment to MAC addresses within IP subnets utilizingnetwork address translation via routers.

In Step 920A, once the specific PN sequence for the local network isconfigured it is searched. Additionally target sub-channels are searchedfor so as to allow repeater configuration and enablement in someembodiments. In Step 925A, the specific control signature is tested todetermine if it is found or not. The “signature” is the target Walshcodes in combination with the PN sequence allowing for the determinationof the desired source signals to be repeated in one embodiment.

If such a signature is not detected, the ECHO device continues to searchfor it in Step 920A. When the control signature is found, Step 930A isperformed. The timing is synchronized to the pilot signal and thecontrol signal. Further, the transmitter's PN sequence is synchronizedto the received PN sequence of the control signature and pilot channelof the composite control channel.

Next, the ECHO device establishes communications with the intendeddestination receive device via receive and transmit control links thatutilize the composite control channel and attempts to receiveinformation from its source transmitter device. The instant ECHO deviceuses the control signature of a specific sub-channel to determine if thedesired ECHO configuration stored in the non-volatile memory is feasibleand that communications with the destination and source IBR or ECHOdevices allow communications. In such a configuration, in someembodiments, the present ECHO device transmits to the destinationreceiving IBR or ECHO device utilizing an assigned orthogonal code addedto the synchronized composite control channel. The destination receivingIBR or ECHO device demodulates the composite control channel looking forthe signature of the instant ECHO device, and demodulates theinformation. The destination device may then forward the receivedinformation to either a central control function or directly to thesource transmitting IBR. Such forwarding allows for the communication offeedback information from the receiving ECHO device to the transmittingsource device for use in optimization of RF parameters. Suchcommunication to the instant ECHO device may utilize a different commoncontrol channel sub-channel and/or a different orthogonal code of thecomposite control channel, from that transmitted by the instant ECHOdevice.

Once communication has been established, at Step 935, the radioparameters in the instant ECHO device are adjusted. Example radioparameters may include: the current gain of the receive and transmitbeam forming parameters, phased array parameters, electrical antennaalignment, electromechanical adjustment, alignment of transmit andreceive antenna elements, feedback cancellation parameters to enhancetransmit to receive isolation, gain margin, stability margin, and C/I ofthe transmitted signal may be measured, adjusted or otherwise monitoredfor achievability. Other RF parameters may include frequency tracking,channel bandwidth, IF frequency optimization and centering as well asreceive and transmit polarization adjustments. These are some specificexamples of radio parameters, which may optimized so as to allow thecurrent ECHO device to achieve particular performance goals as storedduring provisioning.

In Step 940, it is determined if the desired performance goals areachievable based upon the desired configuration and communications areestablished in Step 930A. Additionally, it is determined if thetransmission signatures of the source IBR or ECHO device to be repeatedare detected appropriately. Further, it is determined whethertransmissions to the destination IBR or ECHO device have been receivedand relayed back from the source device. In some embodiments, it isdetermined whether the minimum target for the gain and the desiredisolation margin of the repeater has been appropriately achieved or ifother performance parameters are achievable which are critical to thesystem performance. If the answer is no to these critical configurationtests, processing returns to Step 930A to re-synchronize and determine adifferent desired ECHO configuration for further adjustments made in935A.

Once the desired performance level or configuration is achieved,processing proceeds to Step 945A wherein the composite control channelsare monitored and maintained. Maintenance involves adjustment of RFparameters to maintain the current performance of the communicationlinks as well as the performance of the repeater. ECHO metrics, in someembodiments, are collected on the received signal as well as variousisolation metrics, which may be communicated to the source transmittingECHO or IBR device or to the destination receiving ECHO or IBR device.Additionally, certain metrics or commands are transmitted from thesource transmitting ECHO or IBR device and received at the instant ECHO,thereby allowing for the adjustment of radio parameters to achieve thedesired goals within the instant ECHO. Processing then proceeds to Step950A wherein the ECHO sub-channel signals are determined if they areindividually detected. If they are detected then repeating is enabledand the monitoring and maintaining is continued. If they are notdetected then the ECHO relay or repeating channel is disabled for thespecific receiver corresponding to the undetected ECHO sub-channels sothat indiscriminant repeating of unintended signals is not performed. Insome embodiments, such qualifying of repeater signals is required forFCC regulations in unlicensed bands, allowing such regulation to besatisfied. As a result, indiscriminate repeating is not performed butrepeating of signals by a known transmitter is performed exclusively.

If a signature of a desired target source signal or control channel isnot detected for a period of time, processing then proceeds to Step 930Awherein the process is begun for re-synchronizing. This may requirere-adjusting radio parameters so as to find and locate the correctfrequencies and other radio parameters required to detect ECHOsub-channels, thereby allowing the repeater to be enabled in therepeating step.

FIG. 9B is a message sequence chart for a network of IBR radios and anECHO Relay deployed in a point-to-point (PTP) configuration. FIG. 9Bprovides an example of the qualification and processing of an ECHOdevice within a network of IBRs transmitting to the ECHO device.Additionally a destination device receiving from the ECHO device isdepicted in a protocol diagram as well. IBR-6F-1-Tx1 (9B-05) transmitsFrame A and the composite control channel (embedded within the frame)including sub-channel CCC-IE-11 from the IBR 9B-05 to ECHO-6F-1 (9B-10).The frame is qualified during processing of the composite controlchannel, as described associated with FIG. 9A, during processing timeperiod 9B-51. Note that frame A is not being stored and repeated byECHO-6F-1 (in this embodiment) because no target control signature hasbeen found for a long enough duration so as to qualify the packet to berepeated. Upon the receiving of Frame A+1, the composite control channelincluding sub-channel CCC-IE-11 has been detected and the frame A+1 hasbeen enabled for real time RF repeating per the previously disclosedembodiments. This transmission can be seen as 9B-32. Additionally,further processing is performed during time period processing 9B-52 bythe ECHO device. This processing includes the further detection of thecomposite control channel including the source signal signatures, whichqualify for continued repeating. If such signatures were not found, thenwithin a predetermined time period, the repeating by the ECHO devicewould stop in the current embodiment.

Additionally, information to be communicated to both the destinationdevice (IBR-6F-2) as well as to be relayed to the source device IBR-6F-1is injected during the processing step 9B-52 by ECHO-6F-1. Further,Frame A+1 is repeated during step 9B-32 and includes the compositecontrol channel code CCC-IE-21 along with any other previously presentcomposite control channels. The composite control channel information isreceived by IBR-6F-2 then relayed to IBR-6F-1 within Frame 9B-43 ascomposite control channel CCC-II-22. Any information a destination IBRwishes to communicate to ECHO-6F-1 may be communicated in such a manner.Therefore, any closed loop optimization such as metrics intended for thetransmitting IBR, IBR-6F-1 would be communicated via IBR-6F-2.

As disclosed, the composite control channel is utilized in thecommunication with other nodes of the network (ECHO and IBR devices),and utilized for stability, adaptation, and gain control of the currentECHO device. Additionally, such a composite control channel is for thesatisfaction of a frame by frame qualification of the source that isrepeated. Such qualification allows for the satisfaction of FCC or otherregulatory requirements for operation in specific bands. Such testing ofeach frame may be performed in a number of different manners in variousembodiments. In one embodiment, an entire frame may be detected toqualify for the repeating of the next frame. In alternative embodiments,the delay of the receiver may be used to qualify each signal prior totransmission. For instance, referring FIG. 8F, the modem receives MRx-1signal prior to the delay block 837F-1. Therefore, if the delay of837F-1 is long enough to perform a detection of the control signaturesof the composite control channel, then the ECHO device may be enabledand allow a real time frame by frame qualification.

As described in greater detail in U.S. Pat. No. 8,238,318 and U.S.patent application Ser. No. 13/536,927 and incorporated herein byreference, various antenna configurations may be utilized inpoint-to-point and point-to-multipoint embodiments of the currentinvention. With reference to FIG. 10, a block diagram of an exemplaryIBR antenna array is depicted. Such an array may also be used in part orin entirety as a receive and/or transmit antenna array for an ECHOdevice according to one embodiment of the invention. As the arrayincludes a plurality of antenna panels, each panel may include one ofthe antenna structures or individual antennas having the antennastructures of, for example, antenna structure 803-1. In an ECHO device,normally two such antenna arrays having some or all of the antennapanels depicted in FIG. 10 are utilized with an azimuthal directionalbias different for each array or for each collection of one or more suchantenna panels to optimize link performance between the instant ECHO andthe source and destination devices.

While FIG. 10 is a diagram of an exemplary horizontally arrangedintelligent backhaul radio antenna array, FIG. 11 is a diagram of anexemplary vertically arranged intelligent backhaul radio antenna arraythat may also be used in part or in entirety as a receive and/ortransmit antenna array for an ECHO device according to one embodiment ofthe invention. The depicted antenna arrays shown in FIGS. 10 and 11 areintended for operation in the 5 to 6 GHz band. Analogous versions of thearrangement shown in FIGS. 10 and 11 are possible for any bands withinthe range of at least 500 MHz to 100 GHz as will be appreciated by thoseof skill in the art of antenna design.

The exemplary transmit directive antenna elements depicted in FIGS. 10and 11 include multiple dipole radiators arranged for either dual slant45 degree polarization (FIG. 10) or dual vertical and horizontalpolarization (FIG. 11) with elevation array gain as described in greaterdetail in U.S. patent application Ser. No. 13/536,927 and incorporatedby reference herein. In one exemplary embodiment, each transmitdirective antenna element has an azimuthal beam width of approximately100-120 degrees and an elevation beam width of approximately 15 degreesfor a gain Gqt of approximately 12 dB.

The receive directive antenna elements depicted in FIGS. 10 and 11include multiple patch radiators arranged for either dual slant 45degree polarization (FIG. 10) or dual vertical and horizontalpolarization (FIG. 11) with elevation array gain and azimuthal arraygain as described in greater detail in U.S. patent application Ser. No.13/536,927 and incorporated herein. In one exemplary embodiment, eachreceive directive antenna element has an azimuthal beam width ofapproximately 40 degrees and an elevation beam width of approximately 15degrees for a gain Gqr of approximately 16 dB.

In exemplary ECHO devices, it may be preferable to use only the“receive” antenna elements depicted in FIGS. 10 and 11 for their higherazimuthal directivity properties in both transmit and receive. Forcertain FDD and/or ZDD applications, such exemplary ECHO devices mayhave certain antenna elements assigned specifically for transmit onlywhile in other applications (including certain FDD and/or ZDDscenarios), and especially in TDD applications, the same antennaelements may be usable for both transmit and receive within an exemplaryECHO device.

Preliminary measurements of exemplary antenna arrays similar to thosedepicted in FIG. 10 show isolation of approximately 40 to 50 dB betweenindividual transmit directive antenna elements and individual receivedirective antenna elements of same polarization with an exemplarycircuit board and metallic case behind the radiating elements and aplastic radome in front of the radiating elements. Analogous preliminarymeasurements of exemplary antenna arrays similar to those depicted inFIG. 11 show possible isolation improvements of up to 10 to 20 dB forsimilar directive gain elements relative to FIG. 10. For ECHOapplications where multiple such arrays (or sub-elements thereof) may bephysically and azimuthal directionally disparate as depicted, forexample, in FIG. 14, additional isolation improvements of a further10-20 dB (or more) are expected.

Other directive antenna element types are also known to those of skillin the art of antenna design including certain types described ingreater detail in U.S. patent application Ser. No. 13/536,927 andincorporated herein by reference.

FIG. 12 illustrates a dual-polarity, two-port patch antenna elementincluding feed and grounding points. The arrangement of FIG. 12 may beused as a component of the antenna arrays described herein for usewithin a receive or a transmit antenna panel. In FIG. 12, the dual-portdesign is based on a circular patch antenna 1200. In FIG. 12, twoorthogonal modes are excited by two orthogonal probe feeds 1220 and1210. Each mode excites linearly polarized far-field radiation. Ashorting pin 1230 is provided in the center of the patch to suppress theDC-mode of the patch that would normally be the primary mechanismcreating undesired coupling between the two ports. The construction isbased on two microwave-grade PCBs: one is used as a ground-plane 1202for the patch, and the other contains the etched circular patch 1201.The ground-plane PCB 4302 also provides micro strip feed structure tofeeds 1220 and 1210.

FIG. 13A and FIG. 13B illustrate an exemplary dual-polarity, two port,patch antenna array. The antenna array includes etched patch antennaelements 1301A-H. In FIGS. 13A and 13B, the antenna elements 1301A-Hinclude patch 1201. A shared patch array ground plane 1302, whichcorresponds to the ground plane 1202, is provided for each patchelement. Each patch element 1301A-H includes a two port antenna elementutilizing orthogonal polarization modes. In one embodiment, feeds1310A-H are provided for a first polarization, and feeds 1320A-H areprovided for the second polarization.

In some embodiments, the collective patch antenna array 1300A providesfor a collective two port interface and provides for a common microstrip cooperate feed network integrated with the ground plane 1303 PCB.For example, a first port feeds each of the same polarization feeds1310A-H providing for a polarized sub-array of array 1300A, while asecond port feeds each of the other same polarization feeds 4420A-Hproviding for the other polarized sub-array. In some embodiments, amicro strip cooperative feed network is provided for each polarizationto have a common delay from each array port to each of the respectivepolarization feeds to achieve a desired array factor, and, in turn, adesired array far-field pattern. In yet further embodiments, variationson the relative array port to polarization feeds are provided to achievevarious modified antenna patterns such as a modified beam width, sidelobe levels, or the like.

In some embodiments, the antenna array also includes a grounded fencestructure 1340A and 1340B which provides advantages relating to improvedazimuthal array gain directivity, and side lobe levels, as well aspotentially improved near field isolation from other additional antennastructures. In some embodiments, the antenna array includes supportingstructures 1305A-J to provide structural support of printed patch PCB1302 from ground plane 1303 PCB. It will be appreciated that the patcharray 1300A may be used in the receive or transmit panels of FIG. 10 andFIG. 11, as well as other embodiments disclosed herein.

FIG. 14 is an illustration of an ECHO device according to one embodimentof the invention corresponding to embodiments depicted in FIG. 8F. ECHOdevice enclosure 1420 and the associated antenna structures of theinstant embodiment correspond to embodiments depicted in FIG. 8Fincluding ECHO device 800F.

Antenna panel structure 1410, in the instant embodiment, acts as areceive antenna array and includes a single dual-polarity, two port,patch antenna array 1300A of FIG. 13A, where each port corresponds to arespective port of antenna structures 803F-1 and 803F-2 of FIG. 8F.

Antenna panel structure 1430 in the instant embodiment acts as atransmit antenna array and includes a single dual-polarity, two port,patch antenna array 1300A of FIG. 13A, where each port corresponds to arespective port of antenna structures 803F-4 and 803F-3 of FIG. 8F.

Antenna panel structures 1410 and 1430 are mounted to pole 1460utilizing mounting brackets 1450. Mounting brackets 1450, in the currentembodiment provide for manual mechanical articulation in elevation andazimuth for antenna pattern alignment with the signal source transmitteror target signal destination receiver, and for the minimization ofmutual coupling between antenna panel structures 1410 and 1430, as wellas other factors. Alternative embodiments may provide for anelectromechanically adjustment of such brackets utilizing steppermotors, positioners, or the like as known to one of ordinary skill inthe art. The control of such electromechanical adjustments may beprovided by the ECHO device itself, or by a remote management entityutilizing wired or wireless communication links such as a GPRS module.Additionally, such a GPRS module or the equivalent may be utilized forany of the control communications for the ECHO device as an alternativeto a portion or all the communication provided by the composite controlchannel disclosed previously.

Pole 1460 may be a preexisting pole such as a power pole, a streetlight,or the like. Alternatively, pole 1460 may be installed specifically forthe mounting of the ECHO device and associated antenna structures andbrackets.

The cable assembly 1415 provides for the coupling of receive signalsfrom antenna panel structure 1410 to the ECHO device structure 1420,such coupling providing for two signal paths for the dual polarizedantenna panel 1300A in the current embodiment. Likewise, the cableassembly 1425 provides for the coupling of transmit signals from theECHO device enclosure 1420 to the antenna panel structure 1430, suchcoupling providing for two signal paths for the dual polarized antennapanel 1300A in the current embodiment.

In alternative embodiments more than a single dual polarized antennapanel 1300A may be included in one or more of the antenna panelstructures 1410 and 1430, providing for additional RF ports and signalpaths to and/or from ECHO device enclosure 1420, via cable assemblies1415 and 1425. In addition, alternative antenna structures may be usedin substitution or in addition to one or more of the individual dualpolarized antenna panels 1300A, including within one or more antennapanel structures 1410 and 1430. In yet further embodiments, additionalantenna ports interfacing to the ECHO device enclosure may be providedby additional antenna panel structures for more receive inputs ortransmit outputs. One such embodiment corresponds to the arrangement of800G of FIG. 8G providing for FDD ECHO operation.

One or more of the methodologies or functions described herein may beembodied in a computer-readable medium on which is stored one or moresets of instructions (e.g., software). The software may reside,completely or at least partially, within memory and/or within aprocessor during execution thereof. The software may further betransmitted or received over a network.

The term “computer-readable medium” should be taken to include a singlemedium or multiple media that store the one or more sets ofinstructions. The term “computer-readable medium” shall also be taken toinclude any medium that is capable of storing, encoding or carrying aset of instructions for execution by a machine and that cause a machineto perform any one or more of the methodologies of the presentinvention. The term “computer-readable medium” shall accordingly betaken to include, but not be limited to, solid-state memories, andoptical and magnetic media.

Embodiments of the invention have been described through functionalmodules at times, which are defined by executable instructions recordedon computer readable media which cause a computer, microprocessors orchipsets to perform method steps when executed. The modules have beensegregated by function for the sake of clarity. However, it should beunderstood that the modules need not correspond to discreet blocks ofcode and the described functions can be carried out by the execution ofvarious code portions stored on various media and executed at varioustimes.

It should be understood that processes and techniques described hereinare not inherently related to any particular apparatus and may beimplemented by any suitable combination of components. Further, varioustypes of general purpose devices may be used in accordance with theteachings described herein. It may also prove advantageous to constructspecialized apparatus to perform the method steps described herein. Theinvention has been described in relation to particular examples, whichare intended in all respects to be illustrative rather than restrictive.Those skilled in the art will appreciate that many differentcombinations of hardware, software, and firmware will be suitable forpracticing the present invention. Various aspects and/or components ofthe described embodiments may be used singly or in any combination. Itis intended that the specification and examples be considered asexemplary only, with a true scope and spirit of the invention beingindicated by the claims.

1. (canceled)
 2. A wireless communication repeater device for theenhancement of a multiple input multiple output (MIMO) communicationchannel between a first and a second radio comprising: a receiver forreceiving a plurality of first information streams from a first radio,the plurality of first information streams each having one or moreembedded first control signals; a transmitter for transmitting acomposite signal to the second radio, wherein the composite signalcomprises at least one of the plurality of first information streams andone or more embedded second control signals, the one or more embeddedsecond control signals respectively associated with one or more of theplurality of first information streams; a channel filter for channelfiltering a signal comprising the at least one of the plurality of firstinformation streams and at least one of the one or more embedded firstcontrol signals; a detector for performing detection of at least one ofthe one or more embedded first control signals; a repeater devicecontroller for enabling the transmitter based upon said detection; ademodulator for demodulating at least one of the one or more embeddedfirst control signals to determine first control information; amodulator for generating one or more second control signals; and acoupler for combining the one or more second control signalsrespectively with a signal comprising the at least one of the pluralityof first information streams to produce the composite signal thatcomprises the at least one of the plurality of first information streamsand the one or more second embedded control signals, wherein the one ormore second embedded control signals are usable by the second radio todetermine second control information and to determine information withinsaid second control information for forwarding to the first radio;wherein the wireless communication repeater device is for enhancing theperformance of the MIMO wireless communication channel between the firstradio and the second radio based upon an adjustment of parametersassociated with one or more of: i) the wireless communication repeaterdevice based upon information within the first control information; and,ii) the first radio based upon information within the second controlinformation and, wherein the adjustment of parameters is configured toset a signal level of one of the plurality of the first informationstreams at the wireless communication repeater device relative to signallevels of one or more of the other first information streams of theplurality of first information streams based on a predetermined ratio.3. The wireless communication repeater device of claim 2 wherein each ofsaid one or more embedded first control signals comprises a signaturesignal.
 4. wireless communication repeater device of claim 3 wherein oneof the one or more signature signals is a particular signature signalthat is unique to one of the one or more first information streams. 5.The wireless communication repeater device of claim 4 wherein theparticular signature signal is orthogonal to at least one othersignature signal associated with another first information stream of theplurality of first information streams.
 6. The wireless communicationrepeater device of claim 2 wherein said repeater device adjusts saidparameters associated with said wireless communication repeater devicebased on said information within the first control information.
 7. Thewireless communication repeater device of claim 2 wherein saidtransmitter transmits the composite signal only following detection ofat least one of the one or more associated embedded first controlsignals.
 8. The wireless communication repeater device of claim 2,wherein said wireless communication repeater device is for reducing asignal level difference between a receive signal of at least two of saidplurality of said first information streams at said second radio toenhance the performance of the MIMO wireless channel.
 9. The wirelesscommunication repeater device of claim 8 wherein said receive signalcomprises at least one of the following: i. an LNA output receivesignal; ii. a receive chain output receive signal; iii. an IF coupleroutput receive signal; and iv. IF coupler Modem receive signal.
 10. Thewireless communication repeater device of claim 2 wherein saidparameters are radio frequency (RF) parameters associated with one ormore of a phased array weight and a phased array setting of the wirelesscommunication repeater device and wherein said RF parameters are relatedto at least two of the following: i) a first receiver signal associatedwith said wireless communication repeater device, ii) a second receiversignal associated with said wireless communication repeater device, iii)a first transmitter signal associated with said wireless communicationrepeater device, and iv) a second transmitter signal associated withsaid wireless communication repeater device.
 11. The wirelesscommunication repeater device of claim 2 wherein said parameters areassociated with one or more of a digital transmit beam former weight anda digital transmit beam former setting of the first radio.
 12. Thewireless communication repeater device of claim 2 wherein the adjustmentof parameters associated with the first radio sets the signal level ofone of the plurality of the first information streams at the wirelesscommunication repeater device.
 13. The wireless communication repeaterdevice of claim 2 wherein the adjustment of parameters associated withthe wireless communication repeater device sets the signal level of oneof the plurality of the first information streams detected at the secondradio device.
 14. The wireless communication repeater device of claim 2,wherein the receiver further comprises: a plurality of receive antennastructures coupled to a respective plurality of low noise amplifiers(LNAs) to provide a respective plurality of LNA output receive signals;a plurality of receive chains respectively coupled to said plurality ofLNAs to receive said respective plurality of LNA output receive signalsand to provide a respective plurality of receive chain output receivesignals; and wherein the wireless communication repeater device furthercomprises: a plurality of intermediate frequency (IF) couplers, each ofthe plurality of IF couplers comprising one or more of said couplers,the plurality of IF couplers respectively coupled to said plurality ofreceive chains to receive said respective receive chain output receivesignals and to provide a respective plurality of IF coupler outputreceive signals and a respective plurality of IF coupler Modem receivesignals; a plurality of frequency translating feedback cancellersrespectively coupled to said plurality of IF couplers to respectivelyreceive the IF coupler output receive signals and to provide one or morefrequency translating feedback canceller RF output signals; a pluralityof repeater transmitters, each of the plurality of repeater transmitterscomprising said transmitter, the plurality of repeater transmitters eachrespectively coupled to the plurality of frequency translating feedbackcancellers to receive a respective frequency translating feedbackcanceller RF output signal and to transmit said composite signal; one ormore repeater device modems, wherein one or more of said one or morerepeater device modems further comprise at least one embedded linkprocessor, one or more of said one or more repeater device modemscoupled to one or more of said plurality of IF couplers to receive oneor more IF modem receive signals, and one or more of said one or morerepeater device modems further comprises said detector for performingdetection of at least one of the one or more embedded first controlsignals; wherein said repeater device controller is coupled to said oneor more repeater device modems to exchange information with and providecontrol to the one or more repeater device modems and to further providecontrol associated with said parameters associated with the wirelesscommunication repeater device.
 15. The wireless communication repeaterdevice of claim 14, wherein one or more of the outputs of one or more ofsaid plurality of frequency translating feedback cancellers are furthercoupled to an RF combiner, the RF combiner interposed between at leastone of said plurality of LNAs and said respective plurality of receivechains.
 16. The wireless communication repeater device of claim 14,wherein one of said one or more channel filters are respectivelyinterposed between said plurality of receive chains and said pluralityof IF couplers.
 17. The wireless communication repeater device of claim14, wherein the one or more of said one or more repeater device modemsfurther comprises a second detector for performing detection of at leastone of the associated second embedded control signals to determine thesecond control information.
 18. A wireless communication repeater devicefor the enhancement of a multiple input multiple output (MIMO)communication channel between a first radio and a second radiocomprising: a receiver for receiving, from the first radio, a pluralityof first information streams each having one or more embedded firstcontrol signals; a channel filter for channel filtering a signalcomprising at least one of the plurality of first information streamsand at least one of the one or more embedded first control signals; ademodulator for demodulating at least one of the one or more embeddedfirst control signals to determine associated first control information;a modulator for generating one or more second control signals; whereinsaid receiver comprises: a plurality of receive antenna structurescoupled to a respective plurality of low noise amplifiers (LNAs) toprovide a respective plurality of LNA output receive signals; aplurality of receive chains respectively coupled to said plurality ofLNAs to receive said respective plurality of LNA output receive signalsand to provide a respective plurality of receive chain output receivesignals; a plurality of intermediate frequency (IF) couplers, theplurality of IF couplers respectively coupled to said plurality ofreceive chains to receive said respective receive chain output receivesignals and to provide a respective plurality of IF coupler outputreceive signals and a respective plurality of IF coupler modem receivesignals, wherein at least one of the plurality of IF couplers is furtherfor combining the one or more second control signals respectively with asignal comprising the one or more first information streams to produce acomposite signal that comprises said one or more second control signalsrespectively associated with at least one of the one or more firstinformation streams, wherein the one or more second control signals areusable by the second radio to determine the second control informationand to determine information within said second control information forforwarding to the first radio, the one or more embedded second controlsignals respectively associated with one or more of the plurality offirst information streams, wherein the wireless communication repeaterdevice is for enhancing the performance of the MIMO wirelesscommunication channel between the first and the second radios based uponadjustment of parameters associated with one or more of: i) the repeaterdevice, based upon information within the first control information;and, ii) the first radio, based upon information within the secondcontrol information; a plurality of frequency translating feedbackcancellers respectively coupled to said plurality of IF couplers torespectively receive the IF coupler output receive signals and toprovide one or more frequency translating feedback canceller RF outputsignals; a plurality of repeater transmitters, the plurality of repeatertransmitters each respectively coupled to the plurality of frequencytranslating feedback cancellers to receive a respective frequencytranslating feedback canceller RF output signal, wherein one or more ofthe plurality of repeater transmitters transmit said composite signal;one or more repeater device modems, wherein one or more of said one ormore repeater device modems further comprise at least one embedded linkprocessor, one or more of said one or more repeater device modemscoupled to one or more of said plurality of IF couplers to receive oneor more IF Modem receive signals, and wherein one or more of said one ormore repeater device modems further comprises a detector for performingdetection of at least one of the one or more embedded first controlsignals; a repeater device controller for enabling one or more of therepeater transmitters based upon said detection, wherein said repeaterdevice controller is coupled to the said one or more repeater devicemodems to exchange information with and provide control to the one ormore repeater device modems and to further provide control associatedwith said parameters associated with the repeater device.
 19. Thewireless communication repeater device of claim 18, further comprisingan RF combiner interposed between at least one of said plurality of LNAsand said respective plurality of receive chains, wherein one or moreoutputs of one or more of said plurality of frequency translatingfeedback cancellers are further coupled to the RF combiner.
 20. Thewireless communication repeater device of claim 18, wherein one of saidone or more channel filters are respectively interposed between saidplurality of receive chains and said plurality of IF couplers.